胡杨bZIP转录因子PebZIP26和PebZIP33基因的克隆及功能分析

Cloning and functional analysis of PebZIP26 and PebZIP33 transcription factors from Populus euphratica

bZIP(basic region/leucine zipper motif)是一类在真核生物中分布广泛的超大转录因子家族,参与调节植物的生长发育、衰老、激素调控、能量代谢、病原防御等过程。胡杨是研究抗逆分子机制的模式木本植物,但是关于胡杨的b ZIP功能迄今未见研究报道。本研究从胡杨中克隆得到PebZIP26和PebZIP33两个转录因子的c DNA,经分析,分别编码439与371个氨基酸且PebZIP26与PebZIP33基因的表达受干旱、脱水及盐胁迫诱导。构建植物表达载体,利用农杆菌花序侵染法转化拟南芥,获得Ca MV35S:PebZIP26和Ca MV35S:PebZIP33超表达株系和空载体对照株系。在含有150 mmol/L Na Cl及300 mmol/L甘露醇培养基上,PebZIP26和PebZIP33超表达株系根长均长于野生型,叶片嫩绿,无发黄萎蔫现象;另外,对盆土中的幼苗进行21 d的干旱处理和盐处理,超表达PebZIP26及PebZIP33株系耐旱耐盐性较强,表现为胁迫环境中植株营养生长较好,株高显著高于野生型(WT)及空载体对照株系,干旱复水后,植株存活率为61%及48%,显著高于WT的9%及空载体对照的12%。超表达PebZIP26及PebZIP33株系相比于WT和abf1及tga1(拟南芥同源基因ABF1及TGA1突变体)气孔关闭对外源ABA处理更加敏感,且对氧化胁迫的抗性较强。综上所述,胡杨PebZIP26和PebZIP33转录调节因子可能通过调控气孔开度和活性氧水平及根的生长正向调节植物抗旱耐盐性,进一步丰富了木本植物b ZIP的基因功能认识,为遗传育种提供基因资源及理论依据。

bZIP （basic region/leucine zipper motif） transcription factor is a kind of large transcription factor family and widely distributed in eukaryotic organisms. It participates in the regulation of plant growth and development, senescence, hormone regulation, energy metabolism, pathogen defense, etc. Populus euphratica is a model woody plant to study the molecular mechanism of plant resistance, and has excellent resistance ability to stress, but there are fewer reports about its bZIPs function. We cloned PebZIP26 and PebZIP33 cDNA from Populus euphratica, encoding 439 and 371 amino acids, respectively. The expression of PebZIP26 and PebZIP33 genes were induced by drought, dehydration and salt stress, and then constructed expression vectors. The wild type Arabidopsis thaliana was transformed by Agrobacterium tumefaciens infection, and different strains of CaMV35S ： PebZIP26 and CaMV35S ： PebZIP33 and vacant carrier were obtained. The root length of PebZIP26 and PebZIP33 lines were longer than that of wild type on 150 mmol/L NaC1 and 300 mmol/L Mannitol medium, and had a better leaf statement. 21days drought and salt treatment on each strains of pot plants revealed that, the PebZIP26 and PebZIP33 lines showed better salt tolerance and drought resistance with better nutritional growth and the height of main branch was taller than WT and vacant carrier, and the survival rate after re-watering was 61% and 48% , significantly higher than WT（9% ） and vacant carrier（ 12% ）. In the stomatal closure experiment, the PebZIP26 and PebZIP33 strains were more sensitive to exogenous ABA than WT, abfl and tgal （arabidopsis homologous gene ABF1 and TGA1 mutant）, and also improved the antioxidant activity of plants. Therefore, the study showed that PebZIP26 and PebZIP33 transcription factors could improve the abiotic stress resistance, further enrich the functional study of bZIP genes in woody plants, and provide genetic resources and theoretical basis for genetic breeding.