Weighted Correlation Network Analysis (WGCNA) Reveals the Hub Role of Protein Ubiquitination in the Acquisition of Desiccation Tolerance in Boea Hygrometrica.

Abstract

The first genome sequenced resurrection plant Boea hygrometrica has been shown to be able to survive rapid air-drying after experiencing a slow soil-drying acclimation phase. Weighted gene co-expression analysis was used to study B. hygrometrica transcriptomic datasets. A network containing 22 modules was constructed and seven modules were found to be significantly related to desiccation response by enrichment analysis. Protein ubiquitination was observed to be a common process linked to hub genes in all seven modules. Ubiquitination modified proteins with diversified functions were identified using immunoprecipitation coupled to mass spectrometry. The lowest level of ubiquitination was noted at the full soil drying priming stage, which triggered the accumulation of protective protein BhLEA2. RY motif (CATGCA) was identified from the promoters of ubiquitination related genes that were down-regulated in the desiccated samples. In-silico analysis showed the negative regulation of ubiquitination related genes appeared to be mediated via a B3 domain-containing transcription repressor VAL1. This study suggests that priming may involve the transcriptional regulation of several major processes, and the transcriptional regulation of genes in protein ubiquitination may play a hub role to deliver acclimation signals to posttranslational level in the acquisition of desiccation tolerance in B. hygrometrica.