DEGENERATED LEMMA (DEL) regulates lemma development and affects rice grain yield.

In grass, the lemma is a unique floral organ structure that directly determines grain size and yield. Despite a great deal of research on grain enlargement caused by changes in glume cells, the importance of normal development of the glume for normal grain development has been poorly studied. In this study, we investigated a rice spikelet mutant, degenerated lemma (del), which developed florets with a slightly degenerated or rod-like lemma. More importantly, del also showed a significant reduction in grain length and width, seed setting rate, and 1000-grain weight, which led to a reduction in yield. The results indicate that the mutation of the DEL gene further affects rice grain yield. Map-based cloning shows a single-nucleotide substitution from T to A within Os01g0527600/DEL/OsRDR6, causing an amino acid mutation of Leu-34 to His-34 in the del mutant. Compared with the wild type, the expression of DEL in del was significantly reduced, which might be caused by single base substitution. In addition, the expression level of tasiR-ARF in del was lower than that of the wild type. RT-qPCR results show that the expression of some floral organ identity genes was changed, which indicates that the DEL gene regulates lemma development by modulating the expression of these genes. The present results suggest that the normal expression of DEL is necessary for the formation of lemma and the normal development of grain morphology and therefore has an important effect on the yield. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01297-6.

Six C21 steroidal glycosides from Cynanchum wallichii Wight roots and their multidrug resistance reversal activities.

Six unidentified C21 steroidal glycosides, cynwallosides A-F, as well as twenty-two known compounds, were isolated from the roots of Cynanchum wallichii Wight. The structures of cynwallosides A-F were determined by spectroscopic analysis and acidic hydrolysis. Most of these twenty-eight compounds were found to significantly reverse drug resistance in both the MCF-7/ADR and HepG2/ADM cell lines by suppressing P-gp protein expression. Further investigation revealed that three compounds suppressed P-gp expression by significantly inactivating the JNK and NF-κB pathways.

Field monitoring of Helicoverpa armigera (Lepidoptera: Noctuidae) Cry1Ac insecticidal protein resistance in China (2005-2017).

BACKGROUND: Bt cotton expressing Cry1Ac can efficiently control Helicoverpa armigera, but field-evolved Bt resistance reduces its efficacy. Susceptibility of H. armigera field populations to Cry1Ac protein has been monitored since Bt cotton was commercialized in 1997 in China. Here we report the results of our continued monitoring from 2005 to 2017 to provide important guidelines for sustainably growing cotton. RESULTS: From 13 provinces and regions, 221 populations were sampled and measured. IC50 values (concentration producing 50% inhibition of larval development to third instar) among different strains ranged from 0.004 to 0.212 µg mL-1 , the percentage survival at a diagnostic concentration (IC99 , 1.0 µg mL-1 ) (SUR) ranged from 0% to 22.2%, and the percentage of field populations yielding survivors at diagnostic concentration (PSD) increased from 0 in 2006 and 2007 to 80% in 2015. CONCLUSIONS: Compared to resistance level from 1998 to 2004 and the geographic baseline in different places of China in 1997, Bt resistance of H. armigera field populations to Cry1Ac protein has increased significantly, but failure of Bt cotton has not yet been detected. © 2018 Society of Chemical Industry.