Flower organ identity in rice is mainly determined by the A-, B-, C- and E-class genes, with the majority encoding MADS-box transcription factors.  However, few studies have investigated how the expression of these floral organ identity genes is regulated during flower development.  In this study, we identified a gene named SUPER WOMAN 2 (SPW2), which is necessary for spikelet/floret development in rice by participating in the regulation of the expression of pistil identity genes such as OsMADS3, OsMADS13, OsMADS58 and DL.  In the spw2 mutant, ectopic stigma/ovary-like tissues were observed in the non-pistil organs, including sterile lemma, lemma, palea, lodicule, and stamen, suggesting that the identities of these organs were severely affected by mutations in SPW2.  SPW2 was shown to encode a plant-specific EMF1-like protein that is involved in H3K27me3 modification as an important component of the PRC2 complex.  Expression analysis showed that the SPW2 mutation led to the ectopic expression of OsMADS3, OsMADS13, OsMADS58, and DL in non-pistil organs of the spikelet.  The ChIP-qPCR results showed significant reductions in the levels of H3K27me3 modification on the chromatin of these genes.  Thus, we demonstrated that SPW2 can mediate the process of H3K27me3 modification of pistil-related genes to regulate their expression in non-pistil organs of spikelets in rice.  The results of this study expand our understanding of the molecular mechanism by which SPW2 regulates floral organ identity genes through epigenetic regulation.

The yield of winter wheat is hindered by drought and low temperature in the Loess Plateau of China.  Two common mulching methods to conserve soil moisture, ridge furrows with plastic film mulching (RP) and flat soil surfaces with plastic film mulching (FP) are helpful for wheat production.  Our previous study indicated that FP could improve wheat yield more effectively than RP, but the reason remains unclear.  The effect of mulching method on functional bacteria also needs to be further studied.  In this study, winter wheat was employed to evaluate the impacts of mulching method on soil temperature, moisture content, microorganisms and grain yield.  The results showed that FP had a warming effect when the soil temperature was low and a cooling effect when the temperature was too high.  However, the ability to regulate soil temperature in the RP method was unstable and varied with year.  The lowest negative accumulated soil temperature was found in the FP treatment, which was 20–89 and 43–99% lower than that of the RP and flat sowing with non-film mulching control (NP) treatments, respectively.  Deep soil moisture was better transferred to topsoil for wheat growth in the FP and RP treatments than the NP treatment, which made the topsoil moisture in the two treatments (especially FP) more sufficient than that in the NP treatment during the early growing stage of wheat.  However, due to the limited water resources in the study area, there was almost no difference between treatments in topsoil water storage during the later stage.  The wheat yield in the FP treatment was significantly higher, by 12–16 and 23–56%, respectively, than in the RP and NP treatments.  Significant positive correlations were observed among the negative accumulated soil temperature, spike number and wheat yield.  The Chao1 and Shannon indices in the RP treatment were 17 and 3.9% higher than those in the NP treatment, respectively.  However, according to network relationship analysis, the interspecific relationships of bacteria were weakened in the RP treatment.  Phosphorus solubilizing, ammonification and nitrification bacteria were more active in the RP than in the FP treatment, and microbes with nitrate reduction ability and plant pathogens were inhibited in the RP treatment, which improved nutrient availability and habitat for wheat.

Plant height is a key plant architectural trait that affects the seed yield, harvest index and lodging resistance in Brassica napus L., although the genetic mechanisms affecting plant height remain unclear.  Here, a semi-dwarf mutant, df34, was obtained by ethyl methanesulphonate-induced mutagenesis.  Genetic analysis showed that the semi-dwarf phenotype is controlled by one semi-dominant gene, which was located on chromosome C03 using a bulked segregant analysis coupled with whole-genome sequencing, and this gene was named BnaSD.C3.  Then BnaSD.C3 was fine-mapped to a 297.35-kb segment of the “Darmor-bzh” genome, but there was no potential candidate gene for the semi-dwarf trait underlying this interval.  Furthermore, the interval was aligned to the Zhongshuang 11 reference genome.  Finally, combining structural variation analysis, transcriptome sequencing, phytohormone analyses and gene annotation information, BnaC03G0466900ZS and BnaC03G0478900ZS were determined to be the most likely candidate genes affecting the plant height of df34.  This study provides a novel major locus for breeding and new insights into the genetic architecture of plant height in B. napus

Sugar transporters are essential for osmotic process regulation, various signaling pathways and plant growth and development.  Currently, few studies are available on the function of sugar transporters in sorghum (Sorghum bicolor L.).  In this study, we performed a genome-wide survey of sugar transporters in sorghum.  In total, 98 sorghum sugar transporters (SSTs) were identified via BLASTP.  These SSTs were classified into three families based on the phylogenetic and conserved domain analysis, including six sucrose transporters (SUTs), 23 sugars will eventually be exported transporters (SWEETs), and 69 monosaccharide transporters (MSTs).  The sorghum MSTs were further divided into seven subfamilies, including 24 STPs, 23 PLTs, two VGTs, four INTs, three pGlcT/SBG1s, five TMTs, and eight ERDs.  Chromosomal localization of the SST genes showed that they were randomly distributed on 10 chromosomes, and substantial clustering was evident on the specific chromosomes.  Twenty-seven SST genes from the families of SWEET, ERD, STP, and PLT were found to cluster in eight tandem repeat event regions.  In total, 22 SSTs comprising 11 paralogous pairs and accounting for 22.4% of all the genes were located on the duplicated blocks.  The different subfamilies of SST proteins possessed the same conserved domain, but there were some differences in features of the motif and transmembrane helices (TMH).  The publicly-accessible RNA-sequencing data and real-time PCR revealed that the SST genes exhibited distinctive tissue specific patterns.  Functional studies showed that seven SSTs were mainly located on the cell membrane and membrane organelles, and 14 of the SSTs could transport different types of monosaccharides in yeast.  These findings will help us to further elucidate their roles in the sorghum sugar transport and sugar signaling pathways.