Abstract
Sulfur participates in many important mechanisms and pathways of plant development. The most common source of sulfur in soil –SO42−– is absorbed into root tissue and distributed into aerial part through vasculature system, where it is reduced into sulfite and finally sulfide within the subcellular organs such as chloroplasts and mitochondria and used for cysteine and methionine biosynthesis. MicroRNAs are involved in many regulation pathways by repressing the expression of their target genes. MiR395 family in Arabidopsis thaliana has been reported to be an important regulator involved in sulfate transport and assimilation, and a high-affinity sulphate transporter and three ATP sulfurylases (ATPS) were the target genes of AthmiR395 (Arabidopsis thaliana miR395). We have cloned a miR395 gene from rice (Oryza sativa) and studied its function in plant nutritional response. Our results indicated that in rice, transcript level of OsamiR395 (Oryza sativa miR395) increased under sulfate deficiency conditions, and the two predicted target genes of miR395 were down-regulated under the same conditions. Overexpression of OsamiR395h in tobacco impaired its sulfate homeostasis, and sulfate distribution was also slightly impacted among leaves of different ages. One sulfate transporter (SULTR) gene NtaSULTR2 was identified to be the target of miR395 in Nicotiana tobacum, which belongs to low affinity sulfate transporter group. Both miR395 and NtaSULTR2 respond to sulfate starvation in tobacco.
Highlights
As a rudimental and essential element, sulfur is one of the six macronutrients required for plant growth and participates in many important physiological and biochemical processes
Our results indicate that overexpression of OsamiR395h in tobacco represses sulfate transporter NtaSULTR2, which may play an important role in sulfate transportation and distribution, interrupting sulfate homeostasis and distribution in transgenics
Previous studies on Arabidopsis miR395 have indicated its involvement in sulfate starvation response by repressing the expression of genes in sulfate transportation and assimilation pathways
Summary
As a rudimental and essential element, sulfur is one of the six macronutrients required for plant growth and participates in many important physiological and biochemical processes. Over the course of the past 20 years, essential genes involved in sulfate uptake, distribution and assimilation pathways have been identified and well-studied in different plant species. In Arabidopsis, since the cloning of the first sulfate transporters, AST56 and AST68 two decades ago[4], at least 12 Arabidopsis sulfate transporters belonging to five different groups have been identified[5]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
