BAG蛋白是多功能共伴侣家族。在植物中,发现BAG蛋白在非生物和生物胁迫耐受性中均起作用。然而,拟南芥BAG2的功能在很大程度上仍然未知,而BAG6是植物防御病原体所必需的,尽管尚不清楚BAG6是否参与植物对非生物胁迫的耐受性。这里,我们显示BAG2和BAG6在各种组织中表达,并被盐上调,甘露醇,和热处理以及包括ABA在内的应激相关激素,乙烯,SA。与野生型(WT)相比,bag2,bag6和bag2bag6种子的发芽对ABA的敏感性较低,而BAG2和BAG6过表达品系对ABA过敏。在干旱处理中,bag2,bag6和bag2bag6植物的存活率高于WT,但在热胁迫处理中的存活率较低。始终如一,这些突变体显示了几种胁迫和ABA相关基因的差异表达,如RD29A,RD29B,与WT相比,NCED3和ABI4。此外,与WT相比,这些突变体在干旱和ABA处理后表现出更低的ROS水平,但在热处理后ROS积累更高。这些结果表明,在拟南芥中,BAG2和BAG6与干旱胁迫呈负相关,但在热胁迫中起着积极作用。
The BAG proteins are a family of multi-functional co-chaperones. In plants, BAG proteins were found to play roles both in abiotic and biotic stress tolerance. However, the function of Arabidopsis BAG2 remains largely unknown, whereas
BAG6 is required for plants\' defense to pathogens, although it remains unknown whether
BAG6 is involved in plants\' tolerance to abiotic stresses. Here, we show that both BAG2 and BAG6 are expressed in various tissues and are upregulated by salt, mannitol, and heat treatments and by stress-related hormones including ABA, ethylene, and SA. Germination of bag2,
bag6 and bag2
bag6 seeds is less sensitive to ABA compared to the wild type (WT), whereas BAG2 and
BAG6 overexpression lines are hypersensitive to ABA. bag2,
bag6, and bag2
bag6 plants show higher survival rates than WT in drought treatment but display lower survival rates in heat-stress treatment. Consistently, these mutants showed differential expression of several stress- and ABA-related genes such as RD29A, RD29B, NCED3 and ABI4 compared to the WT. Furthermore, these mutants exhibit lower levels of ROS after drought and ABA treatment but higher ROS accumulation after heat treatment than the WT. These results suggest that BAG2 and
BAG6 are negatively involved in drought stress but play a positive role in heat stress in Arabidopsis.