Expression and Regulation of Plant Amino Acid Transporters and Their Application in Crop Genetic Improvement

Bo PENG Dongyan KONG Lulu

AbstractAmino acid transporters (AATs) play an important role in transport process of various amino acids, which are indispensable in plant growth and development, while many putative AATs have been identified and the complete genomic sequences of the important plants have already been completed by splicing and assembling. There is still little knowledge about the expression, regulation and various biological functions of AATs in plants, including the major food crops. This study mainly reviewed the expression, regulation and various biological functions of AATs in plants, and the application of AATs in crop genetic improvement was also prospected. Thus, this review will provide important information for genetic improvement of staple food crops in plants.

Key wordsAATs; Expression; Regulation; Function; Application



Received: June 29, 2018Accepted: September 30, 2018

Supported by National Natural Science Foundation of China (U1604110, U1404319, 31600992, 31801332); Key Project of Science and Technology in Henan Province (182102110442, 152102110036); Nanhu Scholars Program for Young Scholars of XYNU (2016054); Scientific Research Innovation Project for Postgraduate of XYNU (2018KYJJ47); Major Science and Technology Project in Henan Province (121100110200); National Innovation and Entrepreneurship Training Program for Undergraduates (201810477004); Student Research Fund Project of XYNU (2018DXS066); Key Scientific Research Projects of Universities in Henan Province (19A180030); Institute for Conservation and Utilization of Agrobioresources in Dabie Mountains.

Bo PENG (1980-), male, P. R. China, associate professor, devoted to research about genetic breeding of rice.

*Corresponding author. Email: pengbo@xynu.edu.cn; yhongyu92@163.com.

Amino acids play an important role in the growth, development and metabolism of plants, which is because amino acids are the basic components of various enzymes and proteins in plants, and are precursors or nitrogen sources for nucleic acids, chloroplasts, hormones and secondary metabolites in plants, which are essential for the growth and development in plants. Amino acids can be synthesized by plastids, cytoplasm, mitochondria and peroxisomes in roots or leaf cells of plants［1］, and plants can also absorb amino acids directly from the soil or ultimately convert inorganic nitrogen into amino acids［2］. Some of the amino acids synthesized in plants or absorbed from outside are immediately metabolized, and some are temporarily stored or transported through the phloem to growing parts or sink organs of plants［3-4］. In all these processes, amino acid transporters (AATs) are essential. A large number of studies have also shown that AATs are a key regulatory gene family in plant metabolism［3-9］, and amino acid transporters encoded by them play an important role in plant growth and development.

There are at least 5 AAT gene families, such as amino acidpolyaminecholine (APC) superfamily, sodiumdicarboxylate symporter (SDS) superfamily, neurotransmitter superfamily (NTS), amino acid transporter superfamily 1 (ATF1) and amino acid transporters within the major facilitator superfamily (MFS)［6］. In plants, APC transporter superfamily mainly include two gene families: Amino acid/auxin permease (AAAP) and APC families, of which AAAP family includes amino acid permeases (AAPs), lysinehistidinelike transporters (LHTs) and proline transporters (ProTs), γaminobutyric acid transporters (GATs), ANT1like aromatic, and neutral amino acid transporters and auxin transporters (AUXs )［1,6,8,11］, and APC family included cationic amino acid transporters (CATs), amino acid/choline transporters (ACTs) and polyamine H+symporters (PHSs)［8,12-13］.

In Arabidopsis thaliana, more than 60 AATs have been identified, and 85 AATs that may exist in rice are distributed on 12 chromosomes of rice. However, Most AATs belong to the AAAP superfamily, and some belong to the APC superfamily. Among them, many different AATs are relatively conservative［8］. In the past ten years, a great progress has been made on AATs in the field of plants, the research object has evolved from A. thaliana to important food crops, and more and more members in AAT gene family have bveen separated, cloned, and anazlyed for function in crops［9-12］. Therefore, this study reviewed recent advances on AATs in plant research, including expression, regulation, function, and application of AATs in genetic crop improvement, aiming at providing reference for the indepth study of AATs in plants, especially important food crops.

The Expression of AATs in Plants

Strategies for gene knockout or inhibition of gene expression are often used in the study of gene function, but these mutants do not necessarily produce desired effects when studying the function of A. thaliana AATs. For instance, there is no significant difference between the TDNAinserted mutant of AtAAP3 and the wild type under the same growth condition; and the phenotype of RNAi mutant of AtAAP1 is also the same of normal A. thaliana as control［4,13］. AtAAP2, AtAAP5 and AtAAP6 could be coexpressed with AtAAP3 in roots of A. thaliana, and the amino acid permeases encoded by these three genes and AtAAP3 transport similar amino acids in A. thaliana. Therefore, AtAAP2, AtAAP5 and AtAAP6 may complement the function of AtAAP3 to some extent［4］. Similarly, AtAAP5 is mainly expressed in prophyllum, flowers and seeds, which is similar to the expression pattern of AtAAP1, which might be due to that AtAAP5 can complement the function of AtAAP1 and cause no significant change in the phenotype of AtAAP1 mutant.

The study on the expression of AATs in plants is mainly based on RTPCR, qRTPCR, promoter promoterGUS chimeric expression, insitu hybridization, subcellular localization, immunohistochemistry and promoterGFP protein fusion［4,9,14］. AtAAP2, AtAAP4 and AtAAP5 are mainly experssed in prophyllum, stems and flowers; AtAAP1 is expressed in seeds of A. thaliana; and AtAAP2 is expressed in the microtubules of siliques, leaves, stems, pedicels and mature plants of A. thaliana, which may play an important role in the longdistance transport of amino acids［14-17］. AtAAP3 is mainly expressed in the microtubules of roots, and it is also observed to be transiently expressed in connective tissue before the stamen are split［24］. AtAAP6 is mainly expressed in roots and leaves, and it is also observed to be expressed in parenchyma of xylem. AtAAP6 has a strong affinity to acidic and neutral amino acids, and the amino acid content in the xylem is very low, suggesting that AtAAP3 may play an important role in the process of absorbing amino acids from the xylem［15,18-19］. AtAAP8 is expressed in young siliques and developing seeds, so it is likely to be involved in the transport of amino acids into seeds as well as AtAAP1［3,20］.AtLHT1 gene is found to be expressed on root surface and in pollen, which may be involved in the process by which roots absorb amino acids from the soil, or participate in the process of transporting amino acids to sink organs［21］. AtLHT2 gene has a strong affinity to proline and aspartic acid and is specifically expressed in the tapetal layer of A. thaliana, which means that AtLHT2 gene may be involved in the transport of amino acids to spore cells［22］. Related studies have also been conducted on other AATs in A. thaliana［4,23-25］, such as AtProT1, AtProT2, AtProT3, AtANT1 and the members in APC superfaimly, but their functions and regulatory network in growth and development of A. thaliana still need further study.

Recently, members of AAT gene family in rice were fully expressed and analyzed by three databases and qRTPCR methods［8］. It was found through rice EST database (http://www.ncbi.nlm.nih.gov/unigene/) that most AATs are expressed in rice, many genes are expressed at higher levels in stems, roots, leaves, ears and seeds, and some AATs in rice are specifically expressed. For example, OsBAT5 is specifically expressed in seeds; OsBAT4 is specifically expressed in stems; and OsLHT2, OsATL10 and OsLAT5 are specifically expressed in flowers of rice. It was found through the chip expression database of rice (http://signal.salk.edu/cgibin/RiceGE) that different genes often have different expression patterns, and the AATs in rice can be divided into 6 groups. According to massively parallel (signature sequencing tags, http://mpss.udel.edu/rice/), most AATs are expressed in rice, most of which have low expression levels, and only three genes are strongly expressed (OsAUX1, OsATL5 and OsATL15)［8］. Rice was subjected to nitrogen starvation treatment, and then the expression of AATs was detected. It was found that AATs had different expression patterns, suggesting that they may play important roles in absorption and distribution of nitrogen fertilizer［12］. It was found from the comparison of expression patterns of AATs in rice and A. Thaliana that 26 genes have similar expression patterns in rice and A. Thaliana, the correlation coefficients of homologous genes ranged from 0.7 to 0.9, and their evolutionary relationship was very close［8］. These findings provide important information for future study on expression, subcellular localization, functional analysis, and regulatory mechanisms of AATs in rice. 

The Regulation of AATs in Plants

At present, studies on the regulation of AAT expression are mainly focused on the transcriptional level, and there is no experimental evidence to support that posttranscriptional regulation of AATs exists in plants or AATs are controlled by posttranscriptional modification. A large number of experimental data indicate that amino acid transport is regulated by environmental signals such as light, water, salt stress and nutrients［2-4, 26-32］. When some plants are treated with water or salt stress, proline transporter genes are upregulated, such as AtProT2 gene of A. thaliana, HvProT gene of barley, and McAAT1 gene of Mesembryanthemum crystallinum Linn.［23, 29, 32］. When A. thaliana is treated with water or salt stress, the expression levels of AtAAT6 and AtAAT4 are all reduced［23］. McAAT2 gene is induced to express when the epidermis of root tips and mature roots of M. crystallinum (a salttolerant plant) is under osmotic stress［32］. Researches have found that 21 genes in AATs are significantly upregulated or downregulated when rice is treated with abiotic stress (drought, salt or cold)［8］. OsAAP15, OsATL6 and OsANT3 genes are upregulated when rice is treated with drought, salt or cold stress; OsATL13, OsAAP6, OsAAP11, OsAAP13 and OsAAP5 genes are also upregulated during drought and salt stress treatment; two genes, OsGAT2 and OsCAT6 are upregulated under drought stress; and in salt stress treatment, three genes, OsANT4, OsBAT7 and OsATL11 are all upregulated［8］. Four genes, OsAUX1, OsAAP4, OsBAT4 and OsAAP8 are downregulated during drought, salt or cold stress treatment on rice, suggesting that they may play an important role in abiotic stress.

In A. thaliana, the attack of pathogens may influence the expression of AAT genes. For example, AtLHT1 gene is upregulated in the presence of a pathogen in A. thaliana, which may increase the level of glutamine in cytosol, which in turn affects salicylic acid signaling pathway and ultimately leads to weakening of disease resistance in A. thaliana［33］. Similarly, fungi on the mycorrhizal roots of Lotus corniculatus Linn. (model plant of Leguminosae) can induce the expression of LjLHT1 gene in roots. It was also found that the expression of AAT genes is affected to some extent when the nutrient conditions of plants (whether organic nitrogen or inorganic nitrogen) are changed［3, 23, 26］. When plants are mutated or suffer from overexpression, the transport process of amino acids also changes; and when the cells undergo senescence and apoptosis, their amino acid levels will also change［34-38］, and these processes will affect the expression of specific AAT genes more or less in plants.

Amino acids are important not only to the synthesis of proteins or various enzymes, but also are the precursors of many key compounds (phytohormones and signaling molecules, etc.), such as some compounds that play important roles in the growth, development, metabolism and defense of organisms. Various AATs are located in the center of the complex metabolic regulation network (amino acid transport) between "source" and "storeroom"［39-45］. The activity of nitrogen transporters in plants has an important effect on upstream or downstream substances of various amino acid transporters, while the development of "storeroom" (small flowers, siliques, seeds or grain weight) and the metabolism of plant seeds are regulated by the activity of various amino acid transporters［35, 38-39］. If AATs in plants are mutated or overexpressed, some amino acids may act as signal molecules to cause a series of complex signaling reactions, to thereby alter gene expression, which ultimately leads to changes in phenotype［46-47］. However, which amino acid can be used as a signal molecule? And how is the signal molecule transmitted［3,48-51］? Problems including whether the amino acidpermeable enzymes (Ss1 and Gap1) and kinases (GCN2 kinase) exist in plants remain to be further studied.

Bo PENG et al. Expression and Regulation of Plant AATs and Their Application in Crop Genetic Improvement

The Functions of AATs in Plants

The cloning and functional analysis of AAT genes is most deeply studied in A. thaliana. Among the 8 members of AAP family (AtAAP1–AtAAP8), AtAAP3 and AtAAP5 proteins can transport acidic, neutral and basic amino acids, while other 6 members can generally transport neutral and acidic amino acids［1, 19, 52］. All of the AtAAPs have been localized on the plasma membrane so far, and are often accompanied by transmembrane transport of hydrogen ions when transporting amino acids［2］. AtAAPs participate in a series of physiological processes in plants, such as the absorption of amino acids in soil by roots and longdistance transport of amino acids［35, 38, 52, 53-54］. AtAAP1 gene is mainly expressed in leaves and endosperm and is involved in the transport of amino acids into roots and embryos［16, 35, 54］. AtAAP5 gene plays an important role in the process of absorbing amino acids by roots in soil, and may also be involved in the process of transporting amino acids to embryos［52］. AtAAP6 gene has been shown to play an important role in regulating the composition of molecular sieves by studying the AtAAP6 gene mutant［55］. AtAAP6 gene has been shown to play an important role in regulating the composition of molecular sieves by studying AtAAP6 gene mutants［55］. AtAAP8 gene may be involved in the process of transporting amino acids to endosperm and seeds during the early development of A. thaliana seeds［20］. Amino acid transporters in LHT gene family can transport acidic amino acids, neutral amino acids and basic amino acids, and they are found to be involved in the transport of amino acids from the cell wall into cells and the transport of organic nitrogen to root and mesophyll cells. There also have been reports showed that they participate in the transport of organic nitrogen to pollen and other reproductive organs［3, 22, 56-58］. In addition to studies of these amino acid transporters in A. thaliana, there are some studies in other plants［28, 36, 53］, such as StAAP1, VfAAP1, VfAAP3, PvAAP1 and PtAAP11.

There are also functional studies of AATrelated genes in rice. Thirteen AATs were found in the mutant library of rice, and most of the mutants were found to not affect the yield traits such as tiller number and 1 000grain weight, while osaa49 could reduce rice yield by 37.7%［12］. Some mutants have an important inhibitory effect on the biomass of rice plants (such as mutant osaa5 and osaa7) or a promoting effect (such as mutant osaa24). Further studies have found that these mutants can change the ratio of carbon to nitrogen in rice seed and its relative content［12］. A gene (Bh4) that controls rice husks in black (in Oryza sativa) was also identified in rice and was found to encode an amino acid transporter. This gene has a 22bp deletion mutation in the third exon in cultivated rice, which will cause rice husk color to turn to pale yellow, and it is speculated that Bh4 may be related to domestication［7］. Recently, we cloned from a natural population in rice, a major QTL gene, OsAAP6, which controls the content of grain storage proteins in rice, and belongs to the amino acid permease gene subfamily in the amino acid transporter gene family［9］. OsAAP6 gene is a constitutively expressed gene, which is expressed at a relatively higher level in rice microtubule tissue. OsAAP6 regulates the grain nutritional quality of rice and affects its eating quality by regulating the synthesis and accumulation of grain storage protein and starch in rice, while how does OsAAP6 regulate this process still needs further study.

Application of AATs in Genetic Development of Crops

There are a variety of amino acids in plants that play a very important role in the growth, development and metabolism in plants. This is because amino acids are the basic components for synthesis of various enzymes and proteins, and amino acids are precursors or nitrogen donors of some substances that are important to plant development (such as nucleic acids, chloroplasts, hormones, and secondary metabolites)［59］. However, amino acid transporters play an important role in invivo or intercellular transport of amino acids. In the case of A. thaliana in the dicotyledon, a large number of AAT genes have been successfully isolated and cloned, and the function of these genes have been studied intensively; and in monocotyledonous rice, the members of AAT gene family have been identified in whole genome, their expression patterns and molecular features have been resolved and validated［8,12］, and the related rice mutants have also been tested in the field［12］. Two AAT gene family members have been cloned from rice which is an important food crop, and their functions have been revealed［7,9］. They are found to play an extremely important role in crop genetic improvement. However, the molecular mechanism by which AATencoded amino acid transporters transport amino acids to or from cells is not well understood. How do AATs regulate their functions? And how do they play an important role in the amino acid signaling pathway? It is believed that with the rapid development of biotechnology and functional genomics, more and more AATs are isolated and cloned in model plants, and their biological functions will be gradually analyzed and applied to genetic improvement of major food crops, to accelerate the breeding process of highquality, highyield and multiresistant new crop varieties.

References

［1］ RENTSCH D, SCHMIDT S, TEGEDER M. Transporters for uptake and allocation of organic nitrogen compounds in plants［J］. FEBS Lett, 2007, 581: 2281-2289.

［2］ TEGEDER M, RENTSCH D. Uptake and partitioning of amino acids and peptides［J］. Mol Plant, 2010, 3: 997-1011.

［3］ TEGEDER M. Transporters for amino acids in plant cells: some functions and many unknowns［J］. Curr Opin Plant Biol, 2012, 15: 315-321.

［4］ LIU X, BUSH DR. Expression and transcriptional regulation of amino acid transporters in plants［J］. Amino Acids, 2006, 30: 113-120.

［5］ TEGEDER M, OFFLER CE, FROMMER WB, et al. Amino acid transporters are localized to transfer cells of developing pea seeds［J］. Plant Physiol, 2000, 122: 319-326.

［6］ WIPF D, LUDEWIG U, TEGEDER M, et al. Conservation of amino acid transporters in fungi, plants and animals［J］. Trends Biochem Sci, 2002, 27: 139-147.

［7］ ZHU B F, SI L, WANG Z, et al. Genetic control of a transition from black to strawwhite seed hull in rice domestication［J］. Plant Physiol, 2011, 155: 1301-1311.

［8］ ZHAO H, MA H, YU L, et al. Genomewide survey and expression analysis of amino acid transporter gene family in rice (Oryza sativa L.)［J］. PLoS One, 2012, 7(11): e49210.

［9］ PENG B, KONG HL, LI YB, et al. OsAAP6 functions as an important regulator of grain protein content and nutritional quality in rice［J］. Nat Commun, 2014, 5: 4847.

［10］ PENG B, SUN YF, PANG RH, et al. Research progress of amino acid transporters in plants［J］. Chinese Journal of Tropical Crops, 2016, 37(6): 1238-1243.

［11］ CHANG AB, LIN R, KEITH STUDLEY W, et al. Phylogeny as a guide to structure and function of membrane transport proteins［J］. Mol Membr Biol, 2004, 21: 171-181.

［12］ LU YE, SONG ZY, LU K, et al. Molecular characterization, expression and functional analysis of the amino acid transporter gene family (OsAATs) in rice［J］. Acta Physiol Plant, 2012, 34:1943-1962.

［13］ OKUMOTO S. Root phloemspecific expression of the plasma membrane amino acid proton cotransporter AAP3［J］. J Exp Bot, 2004, 55: 2155-2168.

［14］ ORTIZLOPEZ A, CHANG H, BUSH DR. Amino acid transporters in plants［J］. Biochem Biophysiol Acta, 2000, 1465: 275-280.

［15］ FISCHER WN, KWART M, HUMMEL S, et al. Substrate specificity and expression profile of amino acid transporters (AAPs) in Arabidopsis［J］. J Biol Chem, 1995, 270: 16315-16320.

［16］ HIRNER B, FISCHER WN, RENTSCH D, et al. Developmental control of H+/amino acid permease gene expression during seed development of Arabidopsis［J］. Plant J, 1998, 14: 535-544.

［17］ HSU LC, CHIOU TJ, CHEN L, et al. Cloning a plant amino acid transporter by functional complementation of a yeast amino acid transport mutant［J］. P Natl Acad Sci USA, 1993, 90: 7441-7445.

［18］ OKUMOTO S. High asfinity amino acid transporters specifically expressed in xylem parenchyma and developing seeds of Arabidopsis［J］. J Biol Chem, 2002, 277: 45338-45346.

［19］ FISCHER WN, LOO DD, KOCH W, et al. Low and high affinity amino acid H+cotransporters for cellular import of neutral and charged amino acids［J］. Plant J, 2002, 29: 717-731.

［20］ SCHMIDT R, STRANSKY H, KOCH W. The amino acid permease AAP8 is important for early seed development in Arabidopsis thaliana［J］. Planta, 2007, 226: 805-813.

［21］ CHEN L, BUSH DR. LHT1, a lysine and histidinespecific amino acid transporter in Arabidopsis［J］. Plant Physiol, 1997, 115: 1127-1134.

［22］ LEE YH, TEGEDER M. Selective expression of a novel highaffinity transport system for acidic and neutral amino acids in the tapetum cells of Arabidopsis flowers［J］. Plant J, 2004, 40: 60-74.

［23］ RENTSCH D, HIRNER B, SCHMELZER E, et al. Salt stressinduced proline transporters and salt stressrepressed broad specificity amino acid permeases identified by suppression of a yeast amino acid permeasetargeting mutant［J］. Plant Cell, 1996, 8: 1437-1446.

［24］ SU YH, FROMMER WB, LUDEWIG U. Molecular and functional characterization of a family of amino acid transporters from Arabidopsis［J］. Plant Physiol, 2004, 136: 3104-3113.

［25］ GRALLATH S, WEIMAR T, MEYER A, et al. The AtProT family, compatible solute transporters with similar substrate specificity but differential expression patterns［J］. Plant Physiol, 2005, 137: 117-126.

［26］ DELROT S, ATANASSOVA R, MAUROUSSET L. Regulation of sugar, amino acid and peptide plant membrane transporters［J］. Biochem Biophysiol Acta, 2000, 1465: 281-306.

［27］ CHEN L, ORTIZLOPEZ A, JUNG A, et al. ANT1, an aromatic and neutral amino acid transporter in Arabidopsis［J］. Plant Physiol, 2001, 125: 1813-1820.

［28］ MIRANDA M, BORISJUK L, TEWES A, et al. Amino acid permeases in developing seeds of Vicia faba L.: expression precedes storage protein synthesis and is regulated by amino acid supply［J］. Plant J, 2001, 28: 61-71.

［29］ UEDA A, SHI W, SANMIYA K, et al. Functional analysis of saltinducible proline transporter of barley roots［J］. Plant Cell Physiol, 2001, 42: 1282-1289.

［30］ VAUGHN MW, HARRINGTON GN, BUSH DR. Sucrosemediated transcriptional regulation of sucrose symporter activity in the phloem［J］. P Natl Acad Sci USA, 2002, 99: 10876-10880.

［31］ MOORE B, ZHOU L, ROLLAND F, et al. Role of the Arabidopsis glucose sensor HXK1 in nutrient, light, and hormonal signaling［J］. Science, 2003, 300: 332-336.

［32］ POPOVA OV, DIETZ KJ, GOLLDACK D. Saltdependent expression of a nitrate transporter and two amino acid transporter genes in Mesembryanthemum crystallinum［J］. Plant Mol Biol, 2003, 52: 569-578.

［33］ LIU G, JI Y, BHUIYAN NH, et al. Amino acid homeostasis modulates salicylic acidassociated redox status and defense responses in Arabidopsis［J］. Plant Cell, 2010, 22: 3845-3863.

［34］ MASCLAUXDAUBRESSE C, REISDORFCREN M, ORSEL M. Leaf nitrogen remobilisation for plant development and grain filling［J］. Plant Biol, 2008, 10(1): 23-36.

［35］ SANDERS A, COLLIER R, TRETHEWY A, et al. AAP1 regulates import of amino acids into developing Arabidopsis embryos［J］. Plant J, 2009, 59: 540-552.

［36］ COUTURIER J, DOIDY J, GUINET F, et al. Glutamine, arginine and the amino acid transporter PtCAT11 play important roles during senescence in poplar［J］. Ann Bot, 2010, 105: 1159-1169.

［37］ TAN Q, ZHANG L, GRANT J, et al. Increased phloem transport of Smethylmethionine positively affects sulfur and nitrogen metabolism and seed development in pea plants［J］. Plant Physiol, 2010, 154: 1886-1896.

［38］ ZHANG L, TAN Q, LEE R, et al. Altered xylemphloem transfer of amino acids affects metabolism and leads to increased seed yield and oil content in Arabidopsis［J］. Plant Cell, 2010, 22: 3603-3620.

［39］ DENNISON KL, SPALDING EP. Glutamategated calcium fluxes in Arabidopsis［J］. Plant Physiol, 2000, 124: 1511-1514.

［40］ DUBOS C, HUGGINS D, GRANT GH, et al. A role for glycine in the gating of plant NMDAlike receptors［J］. Plant J, 2003, 35: 800-810.

［41］ KLIEBENSTEIN DJ, AURIA JC, BEHERE AS, et al. Characterization of seedspecific benzoyloxy glucosinolate mutations in Arabidopsis thaliana［J］. Plant J, 2007, 51: 1062-1076.

［42］ GUTIERREZ RA, STOKES TL, THUM K, et al. Systems approach identifies an organic nitrogen responsive gene network that is regulated by the master clock control gene CCA1［J］. P Natl Acad Sci USA, 2008, 105: 4939-4944.

［43］ LU Y, SAVAGE LJ, AJJAWI I, et al. New connections across pathways and cellular processes: industrialized mutant screening reveals novel associations between diverse phenotypes in Arabidopsis［J］. Plant Physiol, 2008, 146: 1482-1500.

［44］ GU L, JONES AD, LAST RL. Broad connections in the Arabidopsis seed metabolic network revealed by metabolite profiling of an amino acid catabolism mutant［J］. Plant J, 2010, 61: 579-590.

［45］ JOSHI V, JOUNG JG, FEI Z, et al. Interdependence of threonine, methionine and isoleucine metabolism in plants: accumulation and transcriptional regulation under abiotic stress［J］. Amino Acids, 2010, 39: 933-947.

［46］ WESTFALL CS, HERRMANN J, CHEN Q, et al. Modulating plant hormones by enzyme action: the GH3 family of acyl acid amido synthetases［J］. Plant Signal Behav, 2010, 5: 1607-1612.

［47］ WALCHLIU P, FILLEUR S, GAN Y, et al. Signaling mechanisms integrating root and shoot responses to changes in the nitrogen supply［J］. Photosynth Res, 2005, 83: 239-250.

［48］ FORDE BG, LEA PJ. Glutamate in plants: metabolism, regulation, and signalling［J］. J Exp Bot, 2007, 58: 2339-2358.

［49］ DIDION T, REGENBERG B, JORGENSEN MU, et al. The permease homologue Ssy1p controls the expression of amino acid and peptide transporter genes in Saccharomyces cerevisiae［J］. Mol Microbiol, 1998, 27: 643-650.

［50］ IIBOSHI Y, PAPST PJ, KAWASOME H, et al. Amino aciddependent control of p70(s6k): Involvement of tRNA aminoacylation in the regulation［J］. J Biol Chem, 1999, 274: 1092-1099.

［51］ DONATON MC, HOLSBEEKS I, LAGATIE O, et al. The Gap1 general amino acid permease acts as an amino acid sensor for activation of protein kinase A targets in the yeast Saccharomyces cerevisiae［J］. Mol Microbiol, 2003, 50: 911-929.

［52］ WEK RC, JIANG HY, ANTHONY TG. Coping with stress: eIF2 kinases and translational control［J］. Biochem Soc T, 2006, 34: 7-11.

［53］ KOCH W, KWART M, LAUBNER M, et al. Reduced amino acid content in transgenic potato tubers due to antisense inhibition of the leaf H+/amino acid symporter StAAP1［J］. Plant J, 2003, 33: 211-220.

［54］ LEE YH, FOSTER J, CHEN J, et al. AAP1 transports uncharged amino acids into roots of Arabidopsis［J］. Plant J, 2007, 50: 305-319.

［55］ HUNT E, GATTOLIN S, NEWBURY HJ, et al. A mutation in amino acid permease AAP6 reduces the amino acid content of the Arabidopsis sieve elements but leaves aphid herbivores unaffected［J］. J Exp Bot, 2010, 61: 55-64.

［56］ HIRNER A. Arabidopsis LHT1 is a highaffinity transporter for cellular amino acid uptake in both root epidermis and leaf mesophyll［J］. Plant Cell, 2006, 18: 1931-1946.

［57］ PENG B, KONG DY, PANG RH, et al. Detection and application of functional markers of Badh2 gene from different fragrant rice varieties in Southern Henan［J］. Southwest China Journal of Agricultural Sciences, 2017, 30(8): 1693-1699. 

［58］ PENG B, SUN YF, LIU L, et al. Role of microscopic observation of rice chalkiness in biological experiments and teaching［J］. Journal of Chifeng University (Natural Science Edition), 2017, 33(6): 6-8.

［59］ PENG B, SUN YF, WANG C, et al. Application?research in the qualities of the major grain crops with near infrared spectroscopy［J］. Journal of Xinyang Normal University (Natural Science Edition), 2017, 20(3): 509-516.

Editor: Yingzhi GUANGProofreader: Xinxiu ZHU



(Continued from page 4)

References

［1］ YANG YQ, ZHANG HM, CHEN YS. Largescale breeding production and application of super male Oreochromis niloticus［J］. Freshwater Fisheries, 2012(4), 75-78.(in Chinese)

［2］ CHEN M, LUO HL, ZHU JJ, et al. Construction and analysis of subtractive library for differentially expressed genes between YY super male tilapia and XY male tilapia［J］. Southwest China Journal of Agricultural Sciences, 2014(3), 1314-1320.(in Chinese)

［3］ YANG YQ, ZHANG HM, CHEN YS. Research of propagation system of WY♀YY♂ type tilapia［J］. Freshwater Fisheries, 2013, 43(1), 89-93.(in Chinese)

［1］ BAO MH, FENG J, CHEN XW, et al. Artificial propagation technology of male yellow catfish［J］. Scientific Fish Farming, 2015(2), 8-9.(in Chinese)

［2］ WAN SL, LI JB, HUANG CQ, et al. Largescale propagation of yellow catfish males using 1yearold YY supermales［J］. Scientific Fish Farming, 2011(1), 8-9.(in Chinese)

［3］ LIU WH. Research progress on artificial gynogenesis in fish［J］. Journal of Anhui Agricultural Sciences, 2008(35), 15519-15521.(in Chinese)

［4］ SUN XW, ZHANG Y, JI X, et al. The genotyping of progenies from two kinds gynogenetic techniques of two fish species［J］. Journal of Fisheries of China, 2008(4), 545-551.(in Chinese)

［5］ CHENG XC, LIN DJ, YOU YL. Influence of temperature on sex differentiation of teleost, Pseudobagrus vachelli［J］. Zoological Research, 2007(1), 73-80.(in Chinese)

［6］ CHEN FJ. Advances in gynogenetic haploids of fish［J］. Journal of Xiangtan Normal University: Natural Science Edition, 2007(3), 15-18.(in Chinese)

［7］ JIA ZY, SUN XW. Progresses in research on gynogenetic and triploid fangzheng silver crucian carp (Carassius auratus auratus L.)［J］. Chinese Journal of Fisheries, 2006(1), 84-89.(in Chinese)

［8］ SUN YD, TAO M, LIU SJ, et al. Induction of gynogenesis of red crucian carp with sperms of Megalobrama amblycephala［J］. Progress in Natural Science, 2006, (12), 1633-1638.(in Chinese)

［9］ LIN DJ, YOU YL. A study on the artificial propagation and masculinizing technique of the teleost, Pseudobagrus vachellii［J］. Journal of Fujian Fisheries, 2004(2), 9-13.(in Chinese)

［10］ LIU LG, ZHAO J, CUI M. Sex determination and artificial sex control in fish［J］. Fisheries Science, 2003(2), 42-45.(in Chinese)

Editor: Chunmei WUProofreader: Xinxiu ZHU