采后失水胁迫调控生姜脆嫩品质的关键基因筛选及功能解析

Ginger (Zingiber officinale) is considered as one of the most popular and preferred spicy plant throughout the world. Dehydration is the major stress factor that causing economic loss of ginger postharvest via significantly decreasing crisp quality. It’s well known that decreasing crisp quality of horticultural products is mainly related to lignification. However, the molecular mechanism of ligification by dehydration during ginger postharvest remains largly unknow. To cope with this stress, the transcriptional regulation genes play a predominant role in transactional regulation of stress response in plants. Recently, 433 transactional regulation genes including MYB、NAC、bHLH、HD-zip etc. were screened by RNA-seq database generated from ginger postharvest with dehydration treatment. In present study, we will firstly identify the role of these transcriptional regulation genes regulating lignification by dehydration during ginger postharvest using VIGS approach. Furthermore, the candidate genes regualting lignification of ginger postharvest will be characterized biochemically and the regulatory network of downstream genes will be identified by screening the RNA-seq data generated from TRV control and gene silenced plants using VIGS approach. The goal of this project is to provide new data for molecular mechanism of regulating crisp quality by dehydration during ginger postharvest from transcription perspective and excavates the genes for further transgenic breeding of new Zingiber officinale Roscoe cultivars.

生姜是全球最重要的辛香类蔬菜。然而，采后失水胁迫导致其脆嫩品质显著下降，商品价值急剧减少，造成巨大的经济损失。已经明确，园艺作物采后脆嫩品质下降主要与木质素合成相关。但是，采后失水胁迫调控生姜木质素合成、进而影响脆嫩品质的分子机理至今尚不明确；筛选和鉴定采后失水胁迫调控生姜木质素合成的关键转录调节基因，便成为解析其分子机理的一个重要课题。前期工作中，申请者通过响应生姜采后失水胁迫基因的RNA-seq分析，已初步筛选到433条转录调节基因，涉及调控木质素生物合成的MYB、NAC、HD-Zip等家族。本课题拟进一步解析候选转录调节基因在采后失水胁迫调控生姜木质素合成中的生物学功能、蛋白产物生化特性及其下游调控网络，旨在从转录层面解析采后失水胁迫调控生姜脆嫩品质的分子机理，挖掘关键转录调节基因，为生姜品质改良分子育种提供基因储备。

生姜是全球重要的辛香类蔬菜，主要分为老姜和仔姜2种。生姜采收时含水量通常高达85%以上，储运过程中极易发生失水胁迫。研究表明采后失水胁迫会引起仔姜木质素积累，显著降低其脆嫩品质。为了挖掘采后失水胁迫引起仔姜脆嫩品质下降的关键基因、解析其生物学功能，项目组以‘渝姜1号’为试材，进行了相关研究。研究结果表明：（1）采后失水胁迫不仅会显著减少仔姜的可溶性糖和可溶性蛋白含量；而且还会显著诱导木质素合成，降低脆嫩品质。（2）采后失水胁迫会诱导仔姜体内活性氧爆发，显著降低仔姜的耐贮性。（3）内源植物激素ABA与SA通过拮抗IAA、CTKs、GAs的作用，增强仔姜采后失水胁迫耐性。（4）通过RNA-seq分析，挖掘到了仔姜中518个受采后失水胁迫持续诱导的关键基因，其中包括ZoHB1。（5）qRT-PCR分析表明，ZoHB1基因受采后失水胁迫持续诱导，其在生姜根茎中有更高的表达量。（6）序列比对分析表明，ZoHB1基因全长1172 bp，其中ORF区为720 bp，编码239个氨基酸。（7）系统进化树分析表明，ZoHB1属于HD-Zip I家族成员，且与拟南芥ATHB13、ATHB23亲缘关系最近。（8）ZoHB1蛋白定位于细胞核且具有强烈的转录激活活性。（9）异源过表达ZoHB1拟南芥植株，不仅具有更高的干旱胁迫耐性，其木质素含量更高。.通过该项目实施，发表了SCI论文2篇，中文核心论文1篇，获省部级一等奖2项，获批实用新型专利5项，获批生姜新品种2个，培养了硕士研究生2名，项目主持人吴林2019年入选重庆英才计划。