Over-expression of the Brachypodium ASR gene, BdASR4, enhances drought tolerance in Brachypodium distachyon
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BdASR4 expression was up-regulated during abiotic stress and hormone treatments. Plants over-expressing BdASR4 improved drought tolerant. BdASR4 may regulate antioxidant activities and transcript levels of stress-related and abscisic acid-responsive genes.
Abiotic stress conditions negatively affect plant growth and developmental processes, causing a reduction in crop productivity. The abscisic acid-, stress-, ripening-induced (ASR) proteins play important roles in the protection of plants from abiotic stress. Brachypodium distachyon L. is a well-studied monocot model plant. However, ASR proteins of Brachypodium have not been widely studied. In this study, five ASR genes of Brachypodium plant were cloned and characterized. The BdASR genes were expressed in response to various abiotic stresses and hormones. In particular, BdASR4 was shown to encode a protein containing a nuclear localization signal in its C-terminal region, which enabled protein localization in the nucleus. To further examine functions of BdASR4, transgenic Brachypodium plants harboring BdASR4 were generated. Over-expression of BdASR4 was associated with strong drought tolerance, and plants over-expressing BdASR4 preserved more water and displayed higher antioxidant enzyme activities than did the wild-type plants. The transcript levels of stress-responsive genes, reactive oxygen species scavenger-associated genes, and abscisic acid-responsive genes tended to be higher in transgenic plants than in WT plants. Moreover, plants over-expressing BdASR4 were hypersensitive to exogenous abscisic acid at the germination stage. Taken together, these findings suggest multiple roles for BdASR4 in the plant response to drought stress by regulating antioxidant enzymes and the transcription of stress- and abscisic acid-responsive genes.
KeywordsDrought Brachypodium distachyon L. Abscisic acid Enzymatic antioxidants Stress-responsive genes
Aba-, stress-, ripening-induced
Green fluorescent protein
Relative water content
This work was supported by the Rural Development Administration, Republic of Korea through their project “Cooperative Research Program for Agriculture Science & Technology Development (Project no. PJ013244)”.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Arenhart RA, Bai Y, Valter de Oliveria LF, Bucker Neto L, Schunemann M, Maraschin FS, Mariath J, Silverio A, Sachetto-Martins G, Margis R, Wang ZY, Margis-Pinheiro M (2014) New insights into aluminum tolerance in rice: the ASR5 protein binds the STAR1 promoter and other aluminum-responsive genes. Mol Plant 7:709–721CrossRefPubMedGoogle Scholar
- Chen H, Nelson R, Sherwood J (1994) Enhanced recovery of transformants of Agrobacterium tumefaciens after freeze-thaw transformation and drug selection. Biotechniques 16(664–668):670Google Scholar
- Li J, Li Y, Yin Z, Jiang J, Zhang M, Guo X, Ye Z, Zhao Y, Xiong H, Zhang Z, Shao Y, Jiang C, Zhang H, An G, Paek NC, Ali J, Li Z (2016b) OsASR5 enhances drought tolerance through a stomatal closure pathway associated with ABA and H2O2 signalling in rice. Plant Biotechnol J 15:183–196CrossRefPubMedPubMedCentralGoogle Scholar
- Liu Q, Kasuga M, Sakuma Y, Abe H, Miura S, Yamaguchi-Shinozaki K, Shinozaki K (1998) Two transcription factors, DREB1 and DREB2, with an EREBP/AP2 DNA binding domain separate two cellular signal transduction pathways in drought-and low-temperature-responsive gene expression, respectively, in Arabidopsis. Plant Cell 10:1391–1406CrossRefPubMedPubMedCentralGoogle Scholar
- Philippe R, Courtois B, McNally KL, Mournet P, El-Malki R, Le Paslier MC, Fabre D, Billot C, Brunel D, Glaszmann JC, This D (2010) Structure, allelic diversity and selection of Asr genes, candidate for drought tolerance, in Oryza sativa L. and wild relatives. Theor Appl Genet 121:769–787CrossRefPubMedGoogle Scholar
- Tran LS, Nakashima K, Sakuma Y, Simpson SD, Fujita Y, Maruyama K, Fujita M, Seki M, Shinozaki K, Yamaguchi-Shinozaki K (2004) Isolation and functional analysis of Arabidopsis stress-inducible NAC transcription factors that bind to a drought-responsive cis-element in the early responsive to dehydration stress 1 promoter. Plant Cell 16:2481–2498CrossRefPubMedPubMedCentralGoogle Scholar
- Virlouvet L, Jacquemot MP, Gerentes D, Corti H, Bouton S, Gilard F, Valot B, Trouverie J, Tcherkez G, Falque M, Damerval C, Rogowsky P, Perez P, Noctor G, Zivy M, Coursol S (2011) The ZmASR1 protein influences branched-chain amino acid biosynthesis and maintains kernel yield in maize under water-limited conditions. Plant Physiol 157:917–936CrossRefPubMedPubMedCentralGoogle Scholar