AtMYB20 is negatively involved in plant adaptive response to drought stress
Background and aims
MYB transcription factors play critical roles in plant development and stress responses. Our objective was to characterize a role of AtMYB20 (AT1G66230) in regulating the ABA-dependent adaptive response to desiccation stress in Arabidopsis.
Sequencing analysis revealed that there is a site located on the AtMYB20 transcript which is potentially base-paired by miR858. To avoid the possible cleavage, a vector with a miR858-resistant version of AtMYB20 under the CaMV 35S promoter (35S:m5AtMYB20) was constructed. The AtMYB20 knock-out mutant myb20 was applied to identifying AtMYB20 functions.
While AtMYB20 was induced by high levels of NaCl, its expression was suppressed by desiccation and cold stresses and abscisic acid (ABA) treatment. Compared with wild-type, AtMYB20 over-expression (35S:m5AtMYB20) seedlings were susceptible to desiccation, whereas MYB20 loss of function mutant myb20 plants displayed resistance to desiccation stress. 35S:m5AtMYB20 plants were less sensitive to ABA, but myb20 mutants were hypersensitive to ABA. This could be validated by the experiment in which treatment with 10 μM ABA for 2 h resulted in constant stomatal opening on leaves of 35S:m5AtMYB20 plants but stomatal closure on myb20 mutant plants. Expression of ABA- and drought stress-responsive marker genes (e.g. ABI3-5 and ABF3-4) was up-regulated in myb20 plants but down-regulated in 35S:m5AtMYB20 plants.
AtMYB20 acts as a negative regulator of plant response to desiccation stress in an ABA-dependent manner.
KeywordsArabidopsis AtMYB20 Desiccation Abscisic acid
This research was supported by The National Research Foundation for the Doctoral Program of Higher Education of China under Grant No B0201100671.
- Chen YH, Yang XY, He K, Liu MH, Li JG, Gao ZF, Lin ZQ, Zhang YF, Wang XX, Qiu XM, Shen YP, Zhang L, Deng XH, Luo JC, Deng XW, Chen ZL, Gu HY, Qu LJ (2006) The MYB transcription factor superfamily of Arabidopsis: expression analysis and phylogenetic comparison with the rice MYB family. Plant Mol Biol 60:107–124CrossRefGoogle Scholar
- German MA, Pillay M, Jeong DH, Hetawal A, Luo S, Janardhanan P, Kannan V, Rymarquis LA, Nobuta K, German R, De Paoli E, Lu C, Schroth G, Meyers BC, Green PJ (2008) Global identification of microRNA–target RNA pairs by parallel analysis of RNA ends. Nat Biotechnol 26:941–946PubMedCrossRefGoogle Scholar
- Riechmann JL, Heard J, Martin G, Reuber L, Jiang CZ, Keddie J, Adam L, Pineda O, Ratcliffe OJ, Samaha RR, Creelman R, Pilgrim M, Broun P, Zhang JZ, Ghandehari D, Sherman BK, Yu G (2000) Arabidopsis transcription factors: genome-wide comparative analysis among eukaryote. Science 290:2105–2110PubMedCrossRefGoogle Scholar
- Shan H, Chen S, Jiang J, Chen F, Chen Y, Gu C, Li P, Song A, Zhu X, Gao H, Zhou G, Li T, Yang X (2012) Heterologous expression of the Chrysanthemun R2R3-MYB transcription factor CmMYB2 enhances drought and salinity tolerance, increases hypersensitivity to ABA and delays flowering in Arabidopsis thaliana. Mol Biotechnol 51:160–173PubMedCrossRefGoogle Scholar
- Yoshida T, Nishimura N, Kitahata N, Kuromori T, Ito T, Asami T, Shinozaki K, Hirayama T (2006) ABA-hypersensitive germination3 encodes a protein phosphatase 2C (AtPP2CA) that strongly regulates abscisic acid signaling during germination among Arabidopsis protein phosphatase 2Cs. Plant Physiol 140:115–126PubMedCentralPubMedCrossRefGoogle Scholar
- Zhou ZS, Song JB, Yang ZM (2012) Genome-wide identification of Brassica napus microRNAs and their targets reveals their differential regulation by cadmium. J Exp Bot 59:3443–3452Google Scholar