Expression analysis of the key genes of fructan remobilization and some physiological traits in wheat under terminal salinity

Abstract

Remobilization of water soluble carbohydrates of wheat stem especially fructan play an important role in grain filling and yield production under stress. To study the effect of salt stress on the key genes involved in this mechanism, 1-sst and 6-sft genes contributed in fructan biosynthesis, 1-feh and ivr genes involved in degradation of fructan and sucrose, respectively, and sut1 as a sucrose transporter gene were examined in Bam as salt-tolerant and Ghods as salt-sensitive varieties using Real-Time PCR. Salt stress was applied since anthesis by irrigation water with EC of 15dSm-1. The experiment was done in greenhouse with three replicates using completely randomized design with factorial arrangement. Sampling was done for stem fructan content at five points with 7-day intervals during seed-filling period and for measurement of prolin and relative water content (RWC( from leaf and gene analysis from stem and seed at day 21 after anthesis. Fructan remobilization was estimated by subtraction of maximum and minimum of fructan content. Results showed that salt stress had a significant influence on RWC and prolin content and induced fructan remobilization along with the stem 1-sst, 1-feh and ivr genes as well as seed sut1 gene in Bam. There was a significant positive correlation between the 1-feh and ivr expression and fructan remobilization under salinity. Based on the obtained results, Bam had higher capacity to hydrolase and remobilize fructan by up-regulation of the critical genes during seed filling, so it was more efficient to use stem reserve carbohydrates and produced higher grain yield under salt stress.

Keywords

• terminal salinity
• fructan remobilization
• gene expression