Deep Sequencing Reveals Early Reprogramming of Root Transcriptomes Upon Infection.

Bacterial wilt caused by the bacterial pathogen is one of the most devastating crop diseases worldwide. The molecular mechanisms controlling the early stage of colonization in the root remain unknown. Aiming to better understand the mechanism of the establishment of infection in root, we established four stages in the early interaction of the pathogen with roots and determined the transcriptional profiles of these stages of infection. A total 2,698 genes were identified as differentially expressed genes during the initial 96 h after infection, with the majority of changes in gene expression occurring after pathogen-triggered root-hair development observed. Further analysis of differentially expressed genes indicated sequential activation of multiple hormone signaling cascades, including abscisic acid (ABA), auxin, jasmonic acid, and ethylene. Simultaneous impairment of ABA receptor genes promoted plant wilting symptoms after infection but did not affect primary root growth inhibition or root-hair and lateral root formation caused by . This indicated that ABA signaling positively regulates root defense to . Moreover, transcriptional changes of genes involved in primary root, lateral root, and root-hair formation exhibited high temporal dynamics upon infection. Taken together, our results suggest that successful infection of on roots is a highly programmed process involving in hormone crosstalk.