Song Qin, Kong Lingfei, Yang Xuerui, Jiao Bo, Hu Jian, Zhang Zhichao, Xu Changzheng, Luo Keming
Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, School of Life Sciences, Southwest University, Chongqing 400715, China.
Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing 400715, China.
Tree Physiol. 2022 Oct 7;42(10):2133-2147. doi: 10.1093/treephys/tpac060.
Drought is one of the main environmental factors that limit plant development and growth. Accordingly, plants have evolved strategies to prevent water loss under drought stress, such as stomatal closure, maintenance of root water uptake, enhancement of stem water transport, and synthesis and deposition of cuticular wax. However, the molecular evidence of cuticular wax biosynthesis regulation in response to drought is limited in woody plants. Here, we identified an MYB transcription factor, Populus tomentosa Carr. MYB transcription factor (PtoMYB142), in response to drought stress from P. tomentosa. Over-expression of PtoMYB142 (PtoMYB142-OE) resulted in increased wax accumulation in poplar leaves, and significantly enhanced drought resistance. We found that the expression of wax biosynthesis genes CER4 and 3-ketoacyl CoA synthase (KCS) were markedly induced under drought stress, and significantly up-regulated in PtoMYB142-OE lines. Biochemical analysis confirmed that PtoMYB142 could directly bind to the promoter of CER4 and KCS6, and regulate their expression in P. tomentosa. Taken together, this study reveals that PtoMYB142 regulates cuticular wax biosynthesis to adapt to water-deficient conditions.
干旱是限制植物发育和生长的主要环境因素之一。因此，植物进化出了在干旱胁迫下防止水分流失的策略，如气孔关闭、维持根系水分吸收、增强茎部水分运输以及表皮蜡质的合成与沉积。然而，木本植物中响应干旱的表皮蜡质生物合成调控的分子证据有限。在此，我们从毛白杨中鉴定出一个响应干旱胁迫的MYB转录因子，即毛白杨MYB转录因子（PtoMYB142）。过表达PtoMYB142（PtoMYB142-OE）导致杨树叶片蜡质积累增加，并显著增强了抗旱性。我们发现，蜡质生物合成基因CER4和3-酮脂酰辅酶A合酶（KCS）的表达在干旱胁迫下显著诱导，并在PtoMYB142-OE株系中显著上调。生化分析证实，PtoMYB142可以直接结合CER4和KCS6的启动子，并在毛白杨中调节它们的表达。综上所述，本研究揭示了PtoMYB142通过调节表皮蜡质生物合成来适应缺水条件。
