Shared and unique transcriptomic changes in chickpea in response to concurrent drought stress and Ralstonia solanacearum pathogen. Cicer arietinum

Chickpea (Cicer arietinum) is the third largest legume grown worldwide and are prone to drought and various pathogen infections. These stresses often occur concurrently in the field conditions. Previous studies in other plant species indicated that plant senses concurrently occurring stresses as new state of stress however, the molecular events in response to that is largely unknown. In the present study, we studied the transcriptome changes in chickpea plants exposed to combination of drought stress and a potential wilt pathogen, Ralstonia solanacearum by microarray analysis. Chickpea plants were exposed to short duration individual drought (SD-drought, soil field capacity, FC-35%), long duration individual drought (LD-drought, FC-30%), short duration individual pathogen stress (SD-pathogen = 2 days pathogen infection), long duration individual pathogen stress (LD-pathogen = 4 days of infection) and short duration and long duration combined stress, SD-combined = 2 days of pathogen infection with progressive drought (FC-40% to FC- 35%), LD combined = 4 days of pathogen infection with progressive drought (FC-35% to 30%).Transcriptome analysis for the leaf samples from above treatment were done by microarray analysis using Agilent ChickpeaGXP_8X60K chip. Result indicated presence of specific molecular events and also some common but tailored events in response to combined stress. Global transcriptional analysis in chickpea leaves exposed to individual and combined drought stress and Ralstonia solanacearum infection. Overall design: Transcriptome analysis was done in the leaf samples of individual and combined stress treated plants by microarray analysis using Agilent ChickpeaGXP_8X60K chip. Chickpea plants were exposed to short duration individual drought (SD-drought, soil field capacity, FC-35%), long duration individual drought (LD-drought, FC-30%), short duration individual pathogen stress (SD-pathogen = 2 days pathogen infection), long duration individual pathogen stress (LD-pathogen = 4 days of infection) and short duration and long duration combined stress, SD-combined = 2 days of pathogen infection with progressive drought (FC-40% to FC- 35%), LD combined = 4 days of pathogen infection with progressive drought (FC-35% to 30%). Two biological replicates were hybridized for each treatment.

鹰嘴豆（Cicer arietinum）是全球第三大栽培豆科作物，易遭受干旱胁迫与多种病原菌侵染，且田间环境中这类胁迫往往同时发生。既往针对其他植物物种的研究表明，植物会将同时发生的多重胁迫感知为一种全新的胁迫状态，但目前学界对其对应的分子调控事件仍知之甚少。本研究通过基因芯片分析（microarray analysis），针对同时遭受干旱胁迫与潜在萎蔫病原菌青枯雷尔氏菌（Ralstonia solanacearum）侵染的鹰嘴豆植株，开展转录组变化分析。

试验设置如下处理：短期单一干旱胁迫（short duration individual drought, SD-drought，土壤田间持水量FC=35%）、长期单一干旱胁迫（long duration individual drought, LD-drought，FC=30%）、短期单一病原菌胁迫（short duration individual pathogen stress, SD-pathogen，病原菌侵染2天）、长期单一病原菌胁迫（long duration individual pathogen stress, LD-pathogen，病原菌侵染4天）、短期复合胁迫（short duration combined stress, SD-combined，伴随渐进式干旱的病原菌侵染2天，FC从40%降至35%）以及长期复合胁迫（long duration combined stress, LD-combined，伴随渐进式干旱的病原菌侵染4天，FC从35%降至30%）。

采用安捷伦（Agilent）ChickpeaGXP_8X60K芯片对上述处理的叶片样本进行基因芯片分析。研究结果显示，复合胁迫响应存在特异性分子事件，同时也存在共通但经过定制化调控的分子事件。本研究针对遭受单一或复合干旱、青枯雷尔氏菌侵染的鹰嘴豆叶片开展全局转录组分析。

整体实验设计：采用安捷伦ChickpeaGXP_8X60K芯片，通过基因芯片分析对单一与复合胁迫处理植株的叶片样本进行转录组分析。试验设置如下处理：短期单一干旱胁迫（short duration individual drought, SD-drought，土壤田间持水量FC=35%）、长期单一干旱胁迫（long duration individual drought, LD-drought，FC=30%）、短期单一病原菌胁迫（short duration individual pathogen stress, SD-pathogen，病原菌侵染2天）、长期单一病原菌胁迫（long duration individual pathogen stress, LD-pathogen，病原菌侵染4天）、短期复合胁迫（short duration combined stress, SD-combined，伴随渐进式干旱的病原菌侵染2天，FC从40%降至35%）以及长期复合胁迫（long duration combined stress, LD-combined，伴随渐进式干旱的病原菌侵染4天，FC从35%降至30%）。每个处理设置两个生物学重复。