Modulation of histone acetylation enables fully mechanized hybrid rice breeding.

Hybrid rice has achieved high grain yield and greatly contributes to food security, but the manual-labour-intensive hybrid seed production process limits fully mechanized hybrid rice breeding. For next-generation hybrid seed production, the use of small-grain male sterile lines to mechanically separate small hybrid seeds from mixed harvest is promising. However, it is difficult to find ideal grain-size genes for breeding ideal small-grain male sterile lines without penalties in the number of hybrid seeds and hybrid rice yield. Here we report that the use of small-grain alleles of the ideal grain-size gene GSE3 in male sterile lines enables fully mechanized hybrid seed production and dramatically increases hybrid seed number in three-line and two-line hybrid rice systems. The GSE3 gene encodes a histone acetyltransferase that binds histones and influences histone acetylation levels. GSE3 is recruited by the transcription factor GS2 to the promoters of their co-regulated grain-size genes and influences the histone acetylation status of their co-regulated genes. Field trials demonstrate that genome editing of GSE3 can be used to immediately improve current elite male sterile lines of hybrid rice for fully mechanized hybrid rice breeding, providing a new perspective for mechanized hybrid breeding in other crops.

Silage Fermentation on Sweet Sorghum Whole Plant for Fen-Flavor Baijiu.

The technology for producing bioethanol from sweet sorghum stalks by solid-state fermentation has developed rapidly in recent years, and has many similarities with traditional Chinese liquor production. However, the product from sweet sorghum stalks was lacking in volatile flavors, and the level of harmful contents were uncertain, therefore it could not be sold as liquor. In this study, the protein, fat, and tannin in the clusters and leaves of sweet sorghum were utilized to increase the content of flavor compounds in the ethanol product through the anaerobic fermentation of Saccharomyces cerevisiae. Meanwhile, the silage fermentation method was used to extend the preservation time of the raw materials and to further enhance the flavors of Fen-flavor liquor, with ethyl acetate as the characteristic flavor. The effects of different feedstock groups on ethyl acetate, ethyl lactate, methanol, acetaldehyde, acetal, fusel oil, total acid, and total ester were evaluated by analyzing the chemical composition of different parts of sweet sorghum and determined by gas chromatograph. The effect of different fermentation periods on the volatile flavor of sweet sorghum Baijiu was evaluated. The yield of the characteristic volatile flavor was increased by the extension of the fermentation time. Sweet sorghum Baijiu with a high ester content can be used as a flavoring liquor, blended with liquor with a shorter fermentation period to prepare the finished Fen-flavor Baijiu, conforming to the Chinese national standard for sale.

The GW2-WG1-OsbZIP47 pathway controls grain size and weight in rice.

Regulation of seed size is a key strategy for improving crop yield and is also a basic biological question. However, the molecular mechanisms by which plants determine their seed size remain elusive. Here, we report that the GW2-WG1-OsbZIP47 regulatory module controls grain width and weight in rice. WG1, which encodes a glutaredoxin protein, promotes grain growth by increasing cell proliferation. Interestingly, WG1 interacts with the transcription factor OsbZIP47 and represses its transcriptional activity by associating with the transcriptional co-repressor ASP1, indicating that WG1 may act as an adaptor protein to recruit the transcriptional co-repressor. In contrary, OsbZIP47 restricts grain growth by decreasing cell proliferation. Further studies reveal that the E3 ubiquitin ligase GW2 ubiquitinates WG1 and targets it for degradation. Genetic analyses confirm that GW2, WG1, and OsbZIP47 function in a common pathway to control grain growth. Taken together, our findings reveal a genetic and molecular framework for the control of grain size and weight by the GW2-WG1-OsbZIP47 regulatory module, providing new targets for improving seed size and weight in crops.