Understanding molecular basis of lateral root development in rice
Regulatory mechanisms for S type and L type lateral root development in which QHB/OsWOX5 and OsWOX10 play opposing roles in controlling each primordium size in rice. Credit: Yoshiaki Inukai

The ability of rice plants to modify their root systems to adapt to the surrounding soil water conditions is a great example of a phenomenon called phenotype plasticity. The exact mechanism behind this was not known. The role of two WOX genes in controlling the root primor size was determined by an international team of researchers.

The short and thin S-type emerge from the primary root of the rice plant. The L-type root system is better suited for water use during periods of osmotic stress because of the difference in their phenotype. The diameter of the root primordium stage is what determines the type of root lateral system. The basis for the differences in primordium size was not known.

Tsubasa Kawai, Akira Yamauchi, and Yoshiaki Inukai from Nagoya University were part of a team that tried to gain a better understanding of the genetic factors that affect the root primordium size. The study provides important insights for improving rice plant resilience to environmental, as the root type determined by its primordium size is an important trait for the growth and maintenance of rice plants under variable water environments.

The seminal root is a type of root that is also called the primary root. They found that the root tip excision in a plant with a defect in the genes for S- and L-type roots resulted in more L-type roots than in the wild plant. The QHB/OsWOX5 gene was found to be responsible for this phenomenon.

The researchers discovered that OsWOX10 was being overexpressed in the L-type roots. The researchers found that OsWOX10's overexpression increased the diameter of the L-type roots, and that the thickness of the L-type roots was affected by the OsWOX10 genes. The expression was found to be related to the activity of QHB and resulted in an increased L-type LR.

They found that the primordial size of the roots was influenced by two genes belonging to the WOX family, QHB and OsWOX10, which were found to have opposing regulatory roles.

Prof. Inukai is hopeful of the potential applications of this discovery, saying that improving root phenotypic plasticity is key to better crop production with more efficient water acquisition. Our findings may lead to the development of unprecedented rice varieties with drought stress tolerance and contribute to securing sustainable rice production for growing population in the world.

More information: Tsubasa Kawai et al, WUSCHEL-related homeobox family genes in rice control lateral root primordium size, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2101846119 Journal information: Proceedings of the National Academy of Sciences Citation: Understanding molecular basis of lateral root development in rice (2022, February 28) retrieved 28 February 2022 from https://phys.org/news/2022-02-molecular-basis-lateral-root-rice.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.