Genome-wide analysis of aquaporin gene family and their responses to water-deficit stress conditions in cassava

摘要

AbstractCassava (Manihot esculentaCrantz) is an important economic crop in tropical countries. Although cassava is considered a drought-tolerant crop that can grow in arid areas, the impact of drought can significantly reduce the growth and yield of cassava storage roots. The discovery of aquaporin molecules (AQPs) in plants has resulted in a paradigm shift in the understanding of plant-water relationships, whereas the relationship between aquaporin and drought resistance in cassava still remains elusive. To investigate the potential role of aquaporin in cassava under water-deficit conditions, 45 putativeMeAQPswere identified in the cassava genome. Six members ofMeAQPs, containing high numbers of water stress-responsive motifs in their promoter regions, were selected for a gene expression study. Two cassava cultivars, which showed different degrees of responses to water-deficit stress, were used to test inin vitroand potted plant systems. The differential expression of all candidateMeAQPswere found in only leaves from the potted plant system were consistent with the relative water content and with the stomatal closure profile of the two cultivars.MePIP2-1andMePIP2-10were up-regulated and this change in their expression might regulate a special signal for water efflux out of guard cells, thus inducing stomatal closure under water-deficit conditions. In addition, the expression profiles of genes in the ABA-dependent pathway revealed an essential correlation with stomatal closure. The potential functions o