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Echinochloa crus-galli Genome Analysis Provides Insight into Its Adaptation and Invasiveness as a Weed

Source: China National Rice Research Institute

A new research progress was achieved by research teams led by Professor Guo Longbiao from China National Rice Research Institute (CNRRI) of Chinese Academy of Agricultural Sciences (CAAS) and Professor Fan Longjiang from Zhejiang University. A new understanding of the molecular mechanisms underlying the extreme adaptation and invasiveness of the hexaploid species Echinochloa crus-galli (E. crus-galli), a pernicious weed in agricultural fields worldwide was acquired.

E. crus-galli is one of the most serious agricultural weeds in the world. Barnyardgrass (E. crus-galli) and rice belong to Gramineae, both have similar biological characteristics like rapid growth rates, plant type, prolonged dormance and others. That is the reason why it is very difficult to control the paddy fields associated with Barnyardgrass via manual weeding. Paddy weeding is currently largely dependent on chemical herbicides. The use of a large number of herbicides not only pollutes the environment, but also increases the cost of production and resistance to Barnyardgrass. Therefore, the selection of "green rice" with inhibition of barnyardgrass is an important way to reduce the use of chemical herbicides.

The genome of barnyardgrass was sequenced, and the defensive secondary metabolites of barnyard grass were synthesized by clustered genes, which were used to compete with rice and resist rice pathogen, which provide an important genetic resource for rice C4 breeding. An extremely large repertoire of genes encoding cytochrome P450 monooxygenases and glutathione S-transferases associated with detoxification are found. Two gene clusters involved in the biosynthesis of an allelochemical 2, 4-dihydroxy-7-methoxy-1, 4-benzoxazin-3-one (DIMBOA) and a phytoalexin momilactone A are found in the E. crus-galli genome, respectively. The allelochemical DIMBOA gene cluster is activated in response to co-cultivation with rice, while the phytoalexin momilactone A gene cluster specifically to infection by pathogenic Pyricularia oryzae. The results provide a new understanding of the molecular mechanisms underlying the extreme adaptation of the weed.

Prof. Guo Longbiao of China National Rice Research Institute of CAAS and Dr. Qiu Jie of Zhejiang University are the co-first authors of this study which is supported by the National Natural Science Foundation of China (Grant No.: 31401453 ). Professor Fan Longjiang from Zhejiang University and Prof. Bai Lianyang of Hunan Academy of Agricultural Sciences are co-corresponding authors. This study was financed by State Key Lab of Rice Biology of China, Zhejiang Natural Science Foundation (Grant No.: LZ17C130001), National Natural Science Foundation of China (Grant No.: 31401453), The study results “Echinochloa crus-galli genome analysis provides insight into its adaptation and invasiveness as a weed” was recently published on Nature Communications, More details can be found in the link below: www.nature.com/articles/s41467-017-01067-5.

By Guo Longbiao