Objectives Expressions of the genes related to panicle development and cell cycle in the mutant rice with clustered spikelets were studied to pave the road for research with an attempt to increase number of grains per panicle on rice plant for improved yield.
Methods The expressions of OsCl-6 and other panicle development-related genes as well as those associated with cell cycle in Neijiang P164 of the mutant variety that bears clustered spikelets on panicle were compared with those in the regular single-floret variety, 9311. Young panicles on Neijiang P164 and 9311 plants that were grown from the seeds in a netted greenhouse were collected for RNA extraction, qRT-PCR, and data analysis.
Results The qRT-PCR results showed higher expression of OsCl-6 at different stages of panicle development in Neijiang P164 than 9311. The expressions of cell cycle dependent kinase genes in 9311 was higher than Neijiang P164, while those of class B cyclins in Neijiang P164 higher than 9311. Neijiang P164 had lower expressions on the panicle development-related genes such as LAX1, WOX3, and RFL than did 9311, but higher on MFS1 and CL-4.
Conclusions The significant differences in the expressions of the genes related to panicle development and cell cycle, including OsCl-6 and B-type cyclins, between Naijiang P164 and 9311 revealed a potential correlation between the genetic makeup and physiology of the two rice varieties. The upregulated OsCl-6 might inhibit the development of secondary branches on rice plants. As increased grains per panicle would directly boost the yield of a rice plant, clustered spikelets would mean improved crop yield.
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