Gene Pleiotropism Of Red Pericarp Gene Rc In Weedy Rice

Weedy rice is a kind of rice variant with strong invasion and environmental plasticity.It has been harming rice production worldwide for a long time.Weedy rice has strong environmental adaptability and can be used as a valuable plant gene resource for the genetic improvement and breeding practice of cultivated rice.Weedy rice is often referred to as red rice because of its red pericarp.The red pericarp of rice is mainly regulated by the two anthocyanin related genes Rc and Rd,and the Rc gene plays the leading role,and Rd is the auxiliary synergistic gene.In this study we use CRISPR/Cas9 system knockout Rc of typical japonica type weedy rice WR04-6.Then conduct comparative study of abiotic stress related traits in seedling stage between knockout line and wild type WR04-6 to further explore the Gene pleiotropism of red pericarp and Rc gene on the environmental adaptability.The main results are as follows:1.In this study,the CRISPR/Cas9 system was used to knock out Rc gene of WR04-6.Based on the vector construction and genetic transformation process introduced in this paper,we successfully created the Rc gene knockout line of weed-rice WR04-6 and obtained two homozygous mutant lines with different mutation types.2.It can be known by comparing the germination rate of weed rice WR04-6 and its two Rc gene knockout lines after harvest.The Rc gene of weedy rice has a certain genetic contribution to dormancy,indicating that the Rc gene has a certain inhibitory effect on preharvest sprouting,so it can partially explain why weedy rice generally has a red pericarp.3.It was found that the germination potential of Rc gene knockout line was slightly lower than that of weed rice WR04-6,and the germination rate of weed rice WR04-6 was faster than that of weed rice WR04-6,and the germination activity of Rc gene mutant was weakened by the determination of the germination potentials of the two knockout lines.This suggests that Rc gene plays a certain role in promoting germination.4.The experimental results of evaluating the coleoptile sheath length of weedy rice WR04-6 and Rc knockout lines under hypoxic stress showed that the elongation of the coleoptile of wild-type Rc rice WR04-6 under hypoxic stress was slower than that of the non-function Rc weed rice WR04-6.5.The germination rate of the two strains under low temperature stress showed that the seed germination of Rc knockout line was slower than that of weedy rice WR04-6,and the maximum germination rate of wild-type weedy rice WR04-6 was higher,indicating that Rc gene may have certain protective effect on embryos under low temperature stress.6.Population genetics analysis found that although the weedy rice group has the lowest genetic diversity within the scope of the genome of the evaluation.However,the diversity of the weedy rice groups in the Rc gene region is relatively high.At the same time the Rc genes in rice weed populations to keep 100% of the frequency,which reflects the environment of red rice type rice group weed diversity of individual choice rather than an individual natural selection.In summary,the comparative study on seed germination and abiotic stress characters between weedy rice WR04-6 and its knocked out line showed that Rc gene played an important role in seedling development and dormancy and was a key pleiotropic gene of environmental adaptability.