Research Projects

Amino acid transporters are membrane-localized carriers involved in the movement of amino acids from the source to sink tissues. They are important participants in various plants processes related to growth, development, and stress tolerance. Genetic manipulation of amino acid transporters can enhance stress tolerance and crop yield. Hence, the present study aims to characterize an unexplored amino acid transporter, OsALT7 (Os01g0825800) which is a homologue of AtAVT6B from Arabidopsis thaliana, a member of a huge family of amino acid transporters AtAVT6. Our prior data in Arabidopsis (Dhatterwal et al., 2021, 2022) showed that the AtAVT6 genes are strongly induced upon exogenous ABA treatment. Generally, phytohormone abscisic acid (ABA) level rises when plants are exposed to abiotic stresses such as drought, salinity, osmotic stresses and also during seed development (Sah et al., 2016), hence confirming the abiotic stress-responsiveness of these transporter genes. Furthermore, in our experiments, ((Dhatterwal et al., 2021, 2022), the expression of AtAVT6B was significantly higher after Nacl treatment while AtAVT6D, another member of family AtAVT6, was considerably stronger in response to both ABA and dehydration compared to other members. These data suggest that AtAVT6B and AtAVT6D are potential candidates to focus on improving the plant salinity and drought tolerance respectively. Additionally, the expression pattern of AtAVT6 genes under nitrogen and sugar starvation conditions in ours as well as other reports ((Dhatterwal et al., 2021, 2022) indicate that the AtAVT6 members may have plausible roles in helping plants to survive nitrogen starvation conditions. Tissue-specific expression analysis showed that the AtAVT6 genes are highly expressed in the senescent leaves. This indicates their involvement in the reallocation of released amino acids due to increased protein degradation in leaves undergoing senescence from source to the site of need, especially to developing sinks such as seeds and flowers. As a proof of concept we have demonstrated that overexpression of AtAVT6 family member has resulted in increased seed weight by twelve and twenty percent in two overexpressed lines of Arabidopsis ((Dhatterwal et al., 2021, 2022). Preliminary analysis in the rice genome indicates OsALT7 as a homologue of AtAVT6B and also a member of a family of amino acid transporters to be existing in rice genome. In this proposal, we envisage to examine this family of amino acid transporters and expect a similar improvement in seed biomass and weight as observed in Arabidopsis thaliana.