Salinity tolerance assessment of rice sucrose transporter antisense lines (OsSUT1) at seedling stage (Oryza sativa var. TaiPai)

In order to evaluate the effects of changing in sucrose partitioning on salt tolerance of rice plants in the seedling stage, a pot experiment was conducted in a split plot based on a randomized complete block design with three replications in the fields of Shahid Chamran University of Ahvaz. The experiment consisted of six lines and cultivars including, wild type (Tai pai), three antisense lines for sucrose transporter SUT1 gene (37-184-8-1, 37-111-7-1 and 34-45-6 1), salinity tolerant (Pokali) and salinity sensitive (Nipponbare) which were exposed to three salinity levels (2, 5 and 16 ds/m sodium chloride). 21 days after salt commencement, shoot dry weight, leaf relative water content, SPAD score, stomatal conductance and total soluble sugars in leaves were evaluated. Increasing in salinity led to increase in levels of soluble sugars and SPAD score and decrease in shoot dry weight, stomatal conductance and leaf relative water content. The results of this study showed that 37-184-8-1 and 37-111-7-1 antisense lines behaved similarly to pokali under salinity stress treatments and were superior in compare to Tai pai as wild type. The expression profiling experiment of sucrose transporter gene family of rice in antisense lines showed relatively reduction in expression of these genes after exposing to salinity. However, this reduction in antisense lines was less than the wild type. According to the results of this study it seems that manipulating the sucrose partitioning in rice plants may improve the salinity tolerance of transgenic lines at seedling stage and this could be suggested as a strategy in breeding programs.