DOI: 10.3724/SP.J.1006.2017.01480

Acta Agronomica Sinica (作物学报) 2017/43:10 PP.1480-1488

Evolutionary Fate and Expression Pattern of Genes Related to Proline Biosyn-thesis in Brassica napus

Proline accumulation is a widespread metabolic adaptation in many organisms in response to various environmental stresses, and it was proved to play protective roles for plants under adverse conditions. Polyploidization is a prominent driving force during plant evolution and many important crops have experienced this process during their evolutionary history. Brassica napus (AACC) is believed to be a newly formed allotetraploid, evolving from the inter-specific hybridization of two diploids, B. rapa (AA) and B. oleracea (CC) followed by chromosome doubling. In this research, we studied the evolutionary fate of genes related to proline synthesis in allotetraploid (B. napus), and its diploids ancestors (B. rapa and B. oleracea), to explore the effect of polyploidition on homologous gene evolution. First, we obtained the genes for proline biosynthesis (P5CSs, OAT) by database searching, and studied the similarities and the expression regulation pattern of homologous genes in allotetraploid (B. napus), in comparison with its diploids progenitors (B. rapa and B. oleracea), in different organs and in response to salt stress. Sequence analysis and phylogenetic analysis revealed that BnaA.P5CS2.a, BnaA.P5CS2.b, and BnaC.P5CS2.c originated from BraA.P5CS2.a, BraA.P5CS2.b, and BolC.P5CS2.a, respectively; BnaA.OAT.a, BnaC.OAT.b originated from BraA.OAT.a and BolC.OAT.a, respectively. And, one copy of gene loss from B. oleracea occurred for BnP5CS2 but not for BnOAT. Expression patterns of these homologous genes in response to salt stress in different organs were also characterized by semi-quantitive RT-PCR. In B. napus, two homologous gene pairs with different origins, BnaA.P5CS2.a and BnaC.P5CS2.c, BnaA.OAT.a and BnaC.OAT.b exhibited biased expression in different organs, implying possible sub-functionalization of P5CS2 and OAT. The genes BnaA.P5CS1.a and BnaC.P5CS1.d with different diploid ancestors were induced by NaCl treatment, and the expression of BnaC.P5CS1.d was higher than that of BnaA.P5CS1.a, showing a biased expression. RT-PCR manifested that preservation of expression pattern of original genes in diploid was found for P5CS1 (BnaA.P5CS1.a and BnaC.P5CS1.d), P5CS2 (BnaA.P5CS2.a and BnaC.P5CS2.c). These results suggest that the gene sequence and expression pattern existing in allotetraploid (B. napus) were conserved, which is benefit to proline accumulation for plant adaptation to environmental stresses.

Key words:Polyploidization,Proline biosynthesis,Biased expression,Salt stress,Sub-functionalization

ReleaseDate:2017-12-07 14:03:28

[1] Kishor P B K, Hong Z L, Miao G H, Hu C A A, Verma D P S. Overexpression of Δ1-pyrroline-5-carboxylate synthetase increases proline production and confers osmotolerance in transgenic plants. Plant Physiol, 1995, 108:1387-1394

[2] Schat H, Sharma S S, Vooijs R. Heavy metal-induced accumulation of free proline in a metal-tolerant and a nontolerant ecotype of Silene vulgaris. Physiol Plant, 1997, 101:477-482

[3] Yang S L, Lan S S, Gong M. Hydrogen peroxide-induced proline and metabolic pathway of its accumulation in maize seedlings. J Plant Physiol, 2009, 166:1694-1699

[4] Tavakoli M, Poustini K, Alizadeh H. Proline accumulation and related genes in wheat leaves under salinity stress. J Agric Sci Tech, 2016, 18:707-716

[5] Dar M I, Naikoo M I, Rehman F, Naushin F, Khan F A. Proline accumulation in plants:roles in stress tolerance and plant development. In:Iqbal N, Nazar R, Khan N A, eds. Osmolytes and Plants Acclimation to Changing Environment:Emerging Omics Technologies. New Delhi:Springer India Press, 2016. pp 155-166

[6] Chaves M M, Flexas J, Pinheiro C. Photosynthesis under drought and salt stress:regulation mechanisms from whole plant to cell. Ann Bot, 2009, 103:551-560

[7] Wu H H, Zou Y N, Rahman M M, Ni Q D, Wu Q S. Mycorrhizas alter sucrose and proline metabolism in trifoliate orange exposed to drought stress. Sci Rep, 2017, 7:42389

[8] Mattioli R, Marchese D, D'Angeli S, Altamura M M, Costantino P, Trovato M. Modulation of intracellular proline levels affects flowering time and inflorescence architecture in Arabidopsis. Plant Mol Biol, 2008, 66:277-288

[9] Mattioli R, Costantino P, Trovato M. Proline accumulation in plants:not only stress. Plant Signal Behav, 2009, 4:1016-1018

[10] Mattioli R, Falasca G, Sabatini S, Altamura M M, Costantino P, Trovato M. The proline biosynthetic genes P5CS1 and P5CS2 play overlapping roles in Arabidopsis flower transition but not in embryo development. Physiol Plant, 2009, 137:72-85

[11] Funck D, Winter G, Baumgarten L, Forlani G. Requirement of proline synthesis during Arabidopsis reproductive development. BMC Plant Biol, 2012, 12:191

[12] Delauney A J, Hu C A A, Kishor P B K, Verma D P S. Cloning of ornithine delta-aminotransferase cDNA from Vigna-Aconitifolia by transcomplementation in Escherichia coli and regulation of proline biosynthesis. J Biol Chem, 1993, 268:18673-18678

[13] Kishor P B K, Sangam S, Amrutha R N, Laxmi P S, Naidu K R, Rao K R S S, Rao S, Reddy K J, Theriappan P, Sreenivasulu N. Regulation of proline biosynthesis, degradation, uptake and transport in higher plants:its implications in plant growth and abiotic stress tolerance. Curr Sci India, 2005, 88:424-438

[14] Wang L, Guo Z, Zhang Y, Wang Y, Yang G, Yang L, Wang R, Xie Z. Characterization of LhSorP5CS, a gene catalyzing proline synthesis in Oriental hybrid lily Sorbonne:molecular modelling and expression analysis. Bot Stud, 2017, 58(1):10

[15] Yoshiba Y, Kiyosue T, Katagiri T, Ueda H, Mizoguchi T, Yamaguchishinozaki K, Wada K, Harada Y, Shinozaki K. Correlation between the induction of a gene for Δ1-pyrroline-5-carboxylate synthetase and the accumulation of proline in Arabidopsis thaliana under osmotic-stress. Plant J, 1995, 7:751-760

[16] Fabro G, Kovacs I, Pavet V, Szabados L, Alvarez M E. Proline accumulation and AtP5CS2 gene activation are induced by plant-pathogen incompatible interactions in Arabidopsis. Mol Plant Microbe In, 2004, 17:343-350

[17] Soltis P S, Soltis D E. The role of genetic and genomic attributes in the success of polyploids. Proc Nati Acad Sci USA, 2000, 97:7051-7057

[18] Buggs R J, Doust A N, Tate J A, Koh J, Soltis K, Feltus F A, Paterson A H, Soltis P S, Soltis D E. Gene loss and silencing in Tragopogon miscellus (Asteraceae):comparison of natural and synthetic allotetraploids. Heredity, 2009, 103:73-81

[19] Wang J, Tian L, Lee H S, Chen Z J. Nonadditive regulation of FRI and FLC loci mediates flowering-time variation in Arabidopsis allopolyploids. Genetics, 2006, 173:965-974

[20] Zhao J W, Buchwaldt L, Rimmer S R, Brkic M, Bekkaoui D, Hegedus D. Differential expression of duplicated peroxidase genes in the allotetraploid Brassica napus. Plant Physiol Bioch, 2009, 47:653-656

[21] Nagahara U. Genome analysis in Brassica with special reference to the experimental formation of B. napus and peculiar mode of fertilisation. J Jpn Bon, 1935, 7:389-452

[22] Blanc G, Wolfe K H. Functional divergence of duplicated genes formed by polyploidy during Arabidopsis evolution. Plant Cell, 2004, 16:1679-1691

[23] Yang Y W, Lai K N, Tai P Y, Li W H. Rates of nucleotide substitution in angiosperm mitochondrial DNA sequences and dates of divergence between Brassica and other angiosperm lineages. J Mol Evol, 1999, 48:597-604

[24] Park J Y, Koo D H, Hong C P, Lee S J, Jeon J W, Lee S H, Yun P Y, Park B S, Kim H R, Bang J W, Plaha P, Bancroft I, Lim Y P. Physical mapping and microsynteny of Brassica rapa ssp. pekinensis genome corresponding to a 222 kbp gene-rich region of Arabidopsis chromosome 4 and partially duplicated on chromosome 5. Mol Genet Genom, 2005, 274:579-588

[25] Wang X, Wang H, Wang J, Sun R, Wu J, Liu S, Bai Y, Mun J H, Bancroft I, Cheng F, Huang S, Li X, Hua W, Freeling M, Pires J C, Paterson A H, Chalhoub B, Wang B, Hayward A, Sharpe A G, Park B S, Weisshaar B, Liu B, Li B, Tong C, Song C, Duran C, Peng C, Geng C, Koh C, Lin C, Edwards D, Mu D, Shen D, Soumpourou E, Li F, Fraser F, Conant G, Lassalle G, King G J, Bonnema G, Tang H, Belcram H, Zhou H, Hirakawa H, Abe H, Guo H, Jin H, Parkin I A, Batley J, Kim J S, Just J, Li J, Xu J, Deng J, Kim J A, Yu J, Meng J, Min J, Poulain J, Hatakeyama K, Wu K, Wang L, Fang L, Trick M, Links M G, Zhao M, Jin M, Ramchiary N, Drou N, Berkman P J, Cai Q, Huang Q, Li R, Tabata S, Cheng S, Zhang S, Sato S, Sun S, Kwon S J, Choi S R, Lee T H, Fan W, Zhao X, Tan X, Xu X, Wang Y, Qiu Y, Yin Y, Li Y, Du Y, Liao Y, Lim Y, Narusaka Y, Wang Z, Li Z, Xiong Z, Zhang Z. The genome of the mesopolyploid crop species Brassica rapa. Nat Genet, 2011, 43:1035-1039

[26] Udall J A, Wendel J F. Polyploidy and crop improvement. Crop Sci, 2006, 46:S3-S14

[27] Wang C P, Lin B, Zhang Y Q, Lin Y H, Liu A H, Hua X J. The evolutionary fate of Δ1-pyrroline-5-carboxylate synthetase 1(P5CS1) genes in allotetraploid Brassica napus. J Syst Evol, 2014, 52:566-579

[28] Tamura K, Dudley J, Nei M, Kumar S. MEGA4:Molecular Evolutionary Genetics Analysis (MEGA) software version 4.0. Mol Biol Evol, 2007, 24:1596-1599

[29] Hua X J, van de Cotte B, Van Montagu M, Verbruggen N. The 5' untranslated region of the At-P5R gene is involved in both transcriptional and post-transcriptional regulation. Plant J, 2001, 26:157-169

[30] Østergaard L, King G J. Standardized gene nomenclature for the Brassica genus. Plant Methods, 2008, 4:10

[31] Hua S, Shamsi I H, Guo Y, Pak H, Chen M, Shi C, Meng H, Jiang L. Sequence, expression divergence, and complementation of homologous ALCATRAZ loci in Brassica napus. Planta, 2009, 230:493-503

[32] Cardenas P D, Gajardo H A, Huebert T, Parkin I A, Iniguez-Luy F L, Federico M L. Retention of triplicated phytoene synthase (PSY) genes in Brassica napus L. and its diploid progenitors during the evolution of the Brassiceae. Theor Appl Genet, 2012, 124:1215-1228

[33] Deng W, Zhou L, Zhou Y T, Wang Y J, Wang M L, Zhao Y. Isolation and characterization of three duplicated PISTILLATA genes in Brassica napus. Mol Biol Rep, 2011, 38:3113-3120

[34] Force A, Lynch M, Pickett F B, Amores A, Yan Y L, Postlethwait J. Preservation of duplicate genes by complementary, degenerative mutations. Genetics, 1999, 151:1531-1545

[35] Adams K L, Liu Z L. Expression partitioning between genes duplicated by polyploidy under abiotic stress and during organ development. Curr Biol, 2007, 17:1669-1674