Ogura cytoplasmic male sterility (Ogura CMS) was first identified in wild radish (Raphanus sativus) and resulted in complete pollen abortion.  However, the molecular mechanism of Ogura CMS in Chinese cabbage remains unclear.  A cytological analysis confirmed nuclear degradation during the late uninucleate stage of pollen development, which diminished by the tricellular stage.  Concurrently, tapetal cells exhibited abnormal enlargement and vacuolation starting from the tetrad stage.  Serious developmental defects were observed in the pollen wall.  During early pollen development, genes associated with cytochrome c and programmed cell death (PCD) were upregulated in the Ogura CMS line, while genes involved in pollen wall mitosis were downregulated.  Conversely, at the late stage of pollen development, peroxisome and autophagy-related genes in the Ogura CMS line were upregulated.  The mitochondrial orf138 gene mutation triggered the PCD process in tapetal cells, leading to their abnormal enlargement and the degradation of their contents, eventually resulting in vacuolation at the tricellular stage.  These tapetal defects hindered the provision of adequate sporopollenin and nutrients to the microspores, consequently leading to abnormal pollen wall development and abnormal mitosis in the microspores.  Ultimately, nuclear dispersion commenced during the late uninucleate stage, and autophagy occurred in the late stage of pollen development.  Consequently, the plant could not produce functional pollen, resulting in male sterility in Chinese cabbage.  Studies of Ogura CMS can promote the production and application of male sterile materials and enrich male sterile resources, which is of great significance for hybrid breeding.

The replacement of winter wheat varieties has contributed significantly to yield improvement worldwide, with remarkable progress in China.  Drawing on two sets of data, production yield from the National Bureau of Statistics of China and experimental yield from literature, this study aims to (1) illustrate the increasing patterns of production yield among different provinces from 1978 to 2018 in China, (2) explore the genetic gain in yield and yield relevant traits through the variety replacement based on experimental yield from 1937 to 2016 in China, and (3) compare the yield gap between experimental yield and production yield.  The results show that both the production and experimental yields significantly increased along with the variety replacement.  The national annual yield increase ratio for the production yield was 1.67% from 1978 to 2018, varying from 0.96% in Sichuan Province to 2.78% in Hebei Province; such ratio for the experimental yield was 1.13% from 1937 to 2016.  The yield gap between experimental and production yields decreased from the 1970s to the 2010s.  This study reveals significant increases in some yield components consequent to variety replacement, including thousand-grain weight, kernel number per spike, and grain number per square meter; however, no change is shown in spike number per square meter.  The biomass and harvest index consistently and significantly increased, whereas the plant height decreased significantly.

This study was conducted to investigate the effects of alternating high temperature on Cry1Ac protein content on Bt cotton cultivars Sikang 1 (SK-1, a conventional cultivar) and Sikang 3 (SK-3, a hybrid cultivar). In 2011 and 2012, cotton plants were subjected to high temperature treatments ranging from 32 to 40°C in climate chambers to investigate the effects of high temperature on boll shell insecticidal protein expression. The experiments showed that significant decline of the boll shell insecticidal protein was detected at temperatures higher than 38°C after 24 h. Based on the results, the cotton plants were treated with the threshold temperature of 38°C from 6:00 a.m. to 6:00 p.m. followed by a normal temperature of 27°C during the remaining night hours (DH/NN) in 2012 and 2013. These treatments were conducted at peak boll growth stage for both cultivars in study periods of 0, 4, 7, and 10 d. Temperature treatment of 32°C from 6:00 a.m. to 6:00 p.m. and 27°C in the remaining hours was set as control. The results showed that, compared with the control, after the DH/NN stress treatment applied for 7 d, the boll shell Cry1Ac protein content level was significantly decreased by 19.1 and 17.5% for SK-1 and by 15.3 and 13.7% for SK-3 in 2012 and 2013, respectively. Further analysis of nitrogen metabolic physiology under DH/NN showed that the soluble protein content and the glutamic pyruvic transaminase (GPT) activities decreased slightly after 4 d, and then decreased sharply after 7 d. The free amino acid content and the protease content increased sharply after 7 d. The changes in SK-1 were greater than those in SK-3. These results suggest that under DH/NN stress, boll shell Cry1Ac protein content decline was delayed. Reduced protein synthesis and increased protein degradation in the boll shell decreased protein content, including Bt protein, which may reduce resistance to the cotton bollworm.

The common vetch (Vicia sativa L.) is a self-pollinated annual forage legume that is widely distributed worldwide.  It has wide adaptability and high nutritional value and is commonly used as an important protein source for livestock feed.  However, pod shattering seriously limits the yield of common vetch.  To clarify the mechanism of pod shattering in common vetch, the pod walls of three shattering-resistant (SR) accessions (B65, B135, and B392) and three shattering-susceptible (SS) accessions (L33, L170, and L461) were selected for transcriptome sequencing.  A total of 17190 differentially expressed genes (DEGs) were identified in the pod wall of B135 and L461 common vetch at 5, 10, 15, 20, and 25 days after anthesis.  KEGG analysis showed that “phenylpropanoid biosynthesis” was the most significantly enriched pathway, and 40 structural genes associated with lignin biosynthesis were identified and differentially expressed in B135 and L461 common vetch.  We analysed the DEGs in the pod wall of three SR and three SS accessions at 15 days after anthesis, and most of the DEGs were consistent with the significant enrichment pathways identified in B135 and L461 common vetch.  The total lignin content of SR accessions was significantly lower than the SS accessions.  The present study lays a foundation for understanding the molecular regulatory mechanism of pod shattering related to lignin biosynthesis in common vetch and provides reference functional genes for breeders to further cultivate shattering-resistant common vetch varieties.