Abscisic acid-induced freezing tolerance in the moss Physcomitrella patens is accompanied by increased expression of stress-related genes
Abscisic acid-induced freezing tolerance in the moss Physcomitrella patens is accompanied by increased expression of stress-related genes
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DOI：
10.1078/0176-1617-00888
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发表时间：
2003-05-01
影响因子：
4.3
通讯作者：
Takezawa, D
中科院分区：
文献类型：
--
作者：
Minami, A;Nagao, M;Takezawa, D
脱落酸（ABA）诱导的基因与高等植物在冷驯化过程中的抗冻性发育有关，但它们在低地植物中的作用尚未确定。我们研究了ABA和寒冷诱导的小立小苔耐冻性和基因表达的变化。在正常生长条件下生长的R - patens原丝体缓慢平衡冷冻至-4℃时，90%以上的细胞死亡，表明原丝体细胞对冷冻敏感。ABA处理24h显著提高了原体的抗冻能力，而冷处理在24h内对原体的抗冻能力仅略有提高。我们检测了从aba处理过的原胞中分离的14个小立壶菌aba应答基因（ppar）的表达。ABA处理后24 h内PPAR基因的表达量均显著增加，其中PPAR基因（PPAR 1 ~ 8和PPAR 14）对低温也有反应，但对ABA的反应要慢得多。高渗NaCl和甘露醇处理提高了原胞的抗冻性，也增加了11个PPAR基因（PPAR2、3、5 ~ 8和10 ~ 14）的表达水平。这些结果表明，ABA和环境胁迫积极影响参与保护原丝体细胞的常见基因的表达，从而导致抗冻性的发展。
Abscisic acid (ABA)-induced genes are implicated in the development of freezing tolerance during cold acclimation in higher plants, but their roles in lower land plants have not been determined. We examined ABA- and cold-induced changes in freezing tolerance and gene expression in the moss Physcomitrella patens. Slow equilibrium freezing to -4degreesC of R patens protonemata grown under normal growth conditions killed more than 90% of the cells, indicating that the protonema cells are freezing-sensitive. ABA treatment for 24h dramatically increased the freezing tolerance of the protonemata, while cold treatment only slightly increased the freezing tolerance within the same period. We examined the expressions of fourteen Physcomitrella patens ABA-responsive genes (PPARs), isolated from ABA-treated protonemata. ABA treatment resulted in a remarkable increase in the expression of all the PPAR genes within 24 h. Several of the PPAR genes (PPAR 1 to 8, and 14) were also responsive to cold, but the response was much slower than that to ABA. Treatment with hyperosmotic concentrations of NaCl and mannitol increased freezing tolerance of protonemata and also increased the expression levels of eleven PPAR genes (PPAR2, 3, 5 to 8, and 10 to 14). These results suggest that ABA and environmental stresses positively affect the expression of common genes that participate in protection of protonema cells leading to the development of freezing tolerance.