Disruption of Amino Acid Transporter LHT1 Leads to Growth Inhibition and Low Yields in Rice

Most research on plant amino acid transporters was conducted in Arabidopsis, thus limiting understanding of their roles in rice. OsLHT1 (Lysine/Histidine transporter) was found to function as a histidine transporter in yeast, but its substrate profile and actual function in living plants remain unclear. Thus, scientists from Guangxi University analyzed the substrate selectivity of OsLHT1 and influence of its disruption on rice growth and fecundity. The findings are published in BMC Plant Biology.

Using two-electrode voltage clamp, the researchers analyzed the substrate selectivity of OsLHT1 in frog oocytes. This showed that OsLHT1 could transport a wide array of amino acids such as basic, neutral, and acidic amino acids, and showed a preference for neutral and acidic amino acids. Using CRISPR-Cas9, two oslht1 mutants were generated leading to loss of function of OsLHT1, inhibiting rice root and shoot growth, which consequently led to reducing grain yields. Further analysis showed that OsLHT1 was expressed in different rice organs, including root, stem, flag leaf, flag leaf sheath, and young panicle. Temporary expression in rice protoplast showed that OsLHT1 was localized to the plasma membrane, which is consistent with its function as an amino acid transporter.

Based on the results, OsLHT1 is an amino acid transporter with wide substrate specificity and with preference for neutral and acidic amino acids, and disruption of OsLHT1 function inhibited rice growth and fecundity.

Read more from BMC Plant Biology.