Functional redundancy of paralogous genes in regulating plant growth and development in rice.

The paralogous genes () are important for root and panicle development in rice ( L.). However, the specific role of paralogous genes is still not clear. To understand the specific roles of paralogs in rice, we generated triple and quadruple mutants by crossing the and double mutants which we previously created. Compared with the 7-day-old wild type, the and triple mutants showed no obvious phenotype variation except that the triple mutant had shorter primary root and shoot. The and triple mutants exhibited a series of developmental abnormalities, including shorter primary roots, longer root hairs, fewer crown roots and lateral roots, shorter and curved shoots. Furthermore, the quadruple mutant displayed more severe phenotypic defects which was lethal. In addition, the expression levels of some hormone signal transduction and crown root development related genes, such as , and , were significantly altered in the stem base of all examined multiple mutants. Taken together, our results demonstrated that the four paralogous genes function redundantly in regulating rice growth and development.