Carneusones A-F, Benzophenone Derivatives from Sponge-Derived Fungus Aspergillus carneus GXIMD00543.

Six benzophenone derivatives, carneusones A-F (1-6), along with seven known compounds (7-13) were isolated from a strain of sponge-derived marine fungus Aspergillus carneus GXIMD00543. Their chemical structures were elucidated by detailed spectroscopic data and quantum chemical calculations. Compounds 5, 6, and 8 exhibited moderate anti-inflammatory activity on NO secretion using lipopolysaccharide (LPS)-induced RAW 264.7 cells with EC50 values of 34.6 ± 0.9, 20.2 ± 1.8, and 26.8 ± 1.7 µM, while 11 showed potent effect with an EC50 value of 2.9 ± 0.1 µM.

TMT-based quantitative proteomic analysis of indica rice cultivars reveals that novel components of the signaling pathways might play a role in grain length regulation.

Grain length is one of the most important rice grain appearance components. To better understand the protein regulated by grain length in indica rice, the tandem mass tag (TMT) labeling combined with LC-MS/MS analysis was used for quantitative identification of differentially regulated proteins by comparing six long-grain cultivars (MeiB, LongfengB, YexiangB, FengtianB, WantaiB, and DingxiangB) to the short-grain cultivar BoB, respectively. A total of 6622 proteins were detected for quantitative analysis by comparing protein content of six long-grain cultivars to the short-grain cultivar, and 715 proteins were significantly regulated, consisting of 336 uniquely over-accumulated proteins and 355 uniquely down-accumulated proteins. KEGG pathway analysis revealed that most of accumulated proteins are involved in metabolic pathways, biosynthesis of secondary metabolites and phenylpropanoid biosynthesis. Four down-accumulated proteins maybe involved in the signaling pathways for grain length regulation. LC-PRM/MS quantitative analysis was used to analyze 10 differentially expressed proteins. The results were almost consistent with the TMT quantitative analysis. qRT-PCR analysis results showed that the transcription level was not always parallel to the protein content. This study identified many novel grain length accumulated proteins through the quantitative proteomics approach, providing candidate genes for further study of grain size regulatory mechanisms. SIGNIFICANCE: Rice grain length is one of the most important characteristics influencing appearance and yield. Six long-grain cultivars (MeiB, LongfengB, YexiangB, FengtianB, WantaiB, and DingxiangB obtained in Guangxi province of China from the 2000s to 2020s) and one short-grain cultivar (BoB obtained in Guangxi province of China in 1980s) were used for comparative analyses. Totally, 715 differentially expressed proteins (DEPs) were identified using TMT-base proteomic analysis. The numbers of DEPs increased as the grain length increased. 4 DEPs may be related to rice's signaling pathways for grain size regulation. A total of 85 DEPs regulated in at least four long-grain cultivars compared with the short-grain cultivar BoB, and 7 proteins were over-accumulated, and 3 proteins were down-accumulated in six long-grain cultivars. These findings provide valuable information to better understand the mechanisms of protein regulation by grain length in rice.

ITRAQ-based quantitative proteomic analysis of japonica rice seedling during cold stress.

Low temperature is one of the important environmental factors that affect rice growth and yield. To better understand the japonica rice responses to cold stress, isobaric tags for a relative and absolute quantification (iTRAQ) labeling-based quantitative proteomics approach was used to detected changes in protein levels. Two-week-old seedlings of the cold tolerant rice variety Kongyu131 were treated at 8°C for 24, 48 and 72 h, then the total proteins were extracted from tissues and used for quantitative proteomics analysis. A total of 5082 proteins were detected for quantitative analysis, of which 289 proteins were significantly regulated, consisting of 169 uniquely up-regulated proteins and 125 uniquely down-regulated proteins in cold stress groups relative to the control group. Functional analysis revealed that most of the regulated proteins are involved in photosynthesis, metabolic pathway, biosynthesis of secondary metabolites and carbon metabolism. Western blot analysis showed that protein regulation was consistent with the iTRAQ data. The corresponding genes of 25 regulated proteins were used for quantitative real time PCR analysis, and the results showed that the mRNA level was not always parallel to the corresponding protein level. The importance of our study is that it provides new insights into cold stress responses in rice with respect to proteomics and provides candidate genes for cold-tolerance rice breeding.

New 3-Acyl Tetramic Acid Derivatives from the Deep-Sea-Derived Fungus Lecanicillium fusisporum.

Seven rare C3-C6 reduced 3-acyl tetramic acid derivatives, lecanicilliumins A-G (1-7), along with the known analogue cladosporiumin D (8), were obtained from the extract of the deep-sea-derived fungus Lecanicillium fusisporum GXIMD00542 within the family Clavipitacae. Their structures were elucidated by extensive spectroscopic data analysis, quantum chemistry calculations and chemical reaction. Compounds 1, 2, 5-7 exhibited moderate anti-inflammatory activity against NF-κB production using lipopolysaccharide (LPS) induced RAW264.7 cells with EC50 values range of 18.49-30.19 µM.

Natural Variation in OsMKK3 Contributes to Grain Size and Chalkiness in Rice.

Rice (Oryza sativa L.) is an important staple food crop for more than half of the world's population. Enhancing the grain quality and yield of rice to meet growing demand remains a major challenge. Here, we show that OsMKK3 encode a MAP kinase kinase that controls grain size and chalkiness by affecting cell proliferation in spikelet hulls. We showed that OsSPL16, GS5, and GIF1 have a substantial effect on the OsMKK3-regulated grain size pathway. OsMKK3 has experienced strong directional selection in indica and japonica. Wild rice accessions contained four OsMKK3 haplotypes, suggesting that the OsMKK3 haplotypes present in cultivated rice likely originated from different wild rice accessions during rice domestication. OsMKK3-Hap1, gs3, and gw8 were polymerized to enhance the grain length. Polymerization of beneficial alleles, such as OsMKK3-Hap1, gs3, gw8, fgr, alk, chalk5, and wx, also improved the quality of hybrid rice. Overall, the results indicated that beneficial OsMKK3 alleles could be used for genomic-assisted breeding for rice cultivar improvement and be polymerized with other beneficial alleles.

Targeted, random mutagenesis of plant genes with dual cytosine and adenine base editors.

Targeted saturation mutagenesis of crop genes could be applied to produce genetic variants with improved agronomic performance. However, tools for directed evolution of plant genes, such as error-prone PCR or DNA shuffling, are limited1. We engineered five saturated targeted endogenous mutagenesis editors (STEMEs) that can generate de novo mutations and facilitate directed evolution of plant genes. In rice protoplasts, STEME-1 edited cytosine and adenine at the same target site with C > T efficiency up to 61.61% and simultaneous C > T and A > G efficiency up to 15.10%. STEME-NG, which incorporates the nickase Cas9-NG protospacer-adjacent motif variant, was used with 20 individual single guide RNAs in rice protoplasts to produce near-saturated mutagenesis (73.21%) for a 56-amino-acid portion of the rice acetyl-coenzyme A carboxylase (OsACC). We also applied STEME-1 and STEME-NG for directed evolution of the OsACC gene in rice and obtained herbicide resistance mutations. This set of two STEMEs will accelerate trait development and should work in any plants amenable to CRISPR-based editing.