A key ABA catabolic gene, OsABA8ox3, is involved in drought stress resistance in rice.
A key ABA catabolic gene, OsABA8ox3, is involved in drought stress resistance in rice.
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关键的 ABA 分解代谢基因 OsABA8ox3 参与水稻的干旱胁迫抗性
DOI：
10.1371/journal.pone.0116646
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Zhu G
中科院分区：
文献类型：
--
作者：
Cai S;Jiang G;Ye N;Chu Z;Xu X;Zhang J;Zhu G
阿坝生物合成基因和catalysts基因的表达通常在植物发育和对环境胁迫的响应中受到共调节。OsNCED 3基因是阿坝生物合成的关键基因，上调其表达可以增强植物的抗旱性，但阿坝分解代谢基因在干旱胁迫中的作用尚不清楚。在本研究中，我们发现OsABA 8 ox 3是OsABA 8 ox家族中在水稻叶片中表达量最高的基因。OsABA 8 ox 3的表达在PEG模拟脱水后的复水过程中被迅速诱导，其趋势与阿坝水平的变化相反。因此，我们构建了水稻OsABA 8 ox 3沉默（RNA干扰，RNAi）和过表达植物。在正常条件下，转基因植株与野生型植株的表型无明显差异。然而，OsABA 8 ox 3 RNAi株系表现出显著的耐旱性提高，而过表达幼苗在脱水10天后的植物存活率方面与野生型相比对干旱胁迫高度敏感。酶活性分析表明，OsABA 8 ox 3 RNAi植株在脱水处理后，超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性高于野生型，丙二醛（MDA）含量低于野生型，表明OsABA 8 ox 3 RNAi植株具有更好的抗氧化胁迫能力和更少的膜损伤。DNA微阵列和实时荧光定量PCR分析结果表明，在OsABA 8 ox 3 RNAi转基因植株中，一组胁迫/干旱相关基因莱亚基因表达增强，转录水平提高。因此，OsABA 8 ox 3基因在调控水稻阿坝水平和抗旱性方面起重要作用。
Expressions of ABA biosynthesis genes and catabolism genes are generally co-regulated in plant development and responses to environmental stress. Up-regulation of OsNCED3 gene, a key gene in ABA biosynthesis, has been suggested as a way to enhance plant drought resistance but little is known for the role of ABA catabolic genes during drought stress. In this study, we found that OsABA8ox3 was the most highly expressed gene of the OsABA8ox family in rice leaves. Expression of OsABA8ox3 was promptly induced by rehydration after PEG-mimic dehydration, a tendency opposite to the changes of ABA level. We therefore constructed rice OsABA8ox3 silencing (RNA interference, RNAi) and overexpression plants. There were no obvious phenotype differences between the transgenic seedlings and wild type under normal condition. However, OsABA8ox3 RNAi lines showed significant improvement in drought stress tolerance while the overexpression seedlings were hypersensitive to drought stress when compared with wild type in terms of plant survival rates after 10 days of unwatering. Enzyme activity analysis indicated that OsABA8ox3 RNAi plants had higher superoxide dismutase (SOD) and catalase (CAT) activities and less malondialdehyde (MDA) content than those of wild type when the plants were exposed to dehydration treatment, indicating a better anti-oxidative stress capability and less membrane damage. DNA microarray and real-time PCR analysis under dehydration treatment revealed that expressions of a group of stress/drought-related genes, i.e. LEA genes, were enhanced with higher transcript levels in OsABA8ox3 RNAi transgenic seedlings. We therefore conclude that that OsABA8ox3 gene plays an important role in controlling ABA level and drought stress resistance in rice.