Key Laboratory of Forest Silviculture and Conservation of the Ministry of Education, Beijing Forestry University, Beijing, People's Republic of China.
Planta. 2013 Aug;238(2):345-56. doi: 10.1007/s00425-013-1894-0. Epub 2013 May 24.
HAP is a ubiquitous transcription factor family which consists of three distinct subunits, namely HAP2, HAP3, and HAP5. Among them, HAP2 and HAP3 subunits have been reported to be involved in plant response to abiotic stress. Here, a HAP5 subunit was identified from Picea wilsonii Mast. and transformed to Arabidopsis to investigate its functions in plant stress response. We found that transformed Arabidopsis with over-expressing PwHAP5 exhibited higher seed germination under salinity, osmotic and abscisic acid (ABA) stress treatment compared to Col-0 plants. The seedlings of transformed Arabidopsis also showed improved tolerance to salinity and decreased sensitivity to ABA treatment. Over-expression of PwHAP5 in Arabidopsis athap5 mutant rescued partly tolerance to NaCl, mannitol and ABA treatment. Furthermore, we examined transcription levels of several stress-related genes in transformed seedlings. Among them, mRNA expression levels of COR15a, KIN1, DREB2A, and RD29A genes were substantially higher in transformed Arabidopsis than those in wild-type (Col-0) plants. Therefore, our data revealed that PwHAP5 plays positive roles in response to salinity, osmotic and ABA stress at different developmental stages in plants, respectively, via possibly regulating stress-related genes.
HAP 是一个普遍存在的转录因子家族，由三个不同的亚基组成，即 HAP2、HAP3 和 HAP5。其中，HAP2 和 HAP3 亚基已被报道参与植物对非生物胁迫的反应。本研究从白皮松中鉴定出一个 HAP5 亚基，并将其转化为拟南芥，以研究其在植物胁迫反应中的功能。结果发现，与 Col-0 植物相比，过表达 PwHAP5 的转化拟南芥在盐、渗透和脱落酸（ABA）胁迫处理下具有更高的种子发芽率。转化拟南芥的幼苗对盐胁迫的耐受性也有所提高，对 ABA 处理的敏感性降低。在 athap5 突变体拟南芥中过表达 PwHAP5 部分挽救了对 NaCl、甘露醇和 ABA 处理的耐受性。此外，我们还检测了转化幼苗中几种与胁迫相关基因的转录水平。其中，COR15a、KIN1、DREB2A 和 RD29A 基因的 mRNA 表达水平在转化拟南芥中明显高于野生型（Col-0）植物。因此，我们的数据表明，PwHAP5 分别通过可能调节与胁迫相关的基因，在植物不同发育阶段对盐、渗透和 ABA 胁迫的反应中发挥积极作用。
