With increasingly frequent extreme weather events, lodging has become an important limiting factor for crop yield and quality and for mechanical harvesting. Lodging resistance is a precondition for “super high yield” crops, and the question of how to achieve lodging resistance to guarantee high yield is an urgent scientific problem. Here, we summarize the anatomical results of lodging resistance stems and find that the lodging resistance of stems is closely related to stem components. Therefore, we focus on the roles of lignin, cellulose and hemicellulose, which provide stem rigidity and strength, in crop lodging resistance. By combing the synthetic regulatory molecular network of lignin, cellulose and hemicellulose, we find that only some of the genes involved in the biosynthesis and regulation of lignin, cellulose, and hemicellulose have been shown to significantly affect lodging resistance. However, many relevant genes remain to be studied in sufficient detail to determine whether they can be applied in breeding for lodging resistance. This work provides valuable information for future studies of lodging resistance.

Heat stress (HS), caused by extremely high temperatures, is one of the most severe forms of abiotic stress in pepper. In the present study, we studied the transcriptome and metabolome of a heat-tolerant cultivar (17CL30) and a heat-sensitive cultivar (05S180) under HS. Briefly, we identified 5754 and 5756 differentially expressed genes (DEGs) in 17CL30 and 05S180, respectively. Moreover, we also identified 94 and 108 differentially accumulated metabolites (DAMs) in 17CL30 and 05S180, respectively. Interestingly, there were many common HS-responsive genes (approximately 30%) in both pepper cultivars, despite the expression patterns of these HS-responsive genes being different in both cultivars. Notably, the expression changes of the most common HS-responsive genes were typically much more significant in 17CL30, which might explain why 17CL30 was more heat tolerant. Similar results were also obtained from metabolome data, especially amino acids, organic acids, flavonoids, and sugars. The changes in numerous genes and metabolites emphasized the complex response mechanisms involved in HS in pepper. Collectively, our study suggested that the glutathione metabolic pathway played a critical role in pepper response to HS and the higher accumulation ability of related genes and metabolites might be one of the primary reasons contributing to the heat resistance.

Synthetic microbial community (SynCom) application is efficient in promoting crop yield and soil health. However, few studies have been conducted to enhance pepper growth via modulating rhizosphere microbial communities by SynCom application. This study aimed to investigate how SynCom inoculation at the seedling stage impacts pepper growth by modulating the rhizosphere microbiome using high-throughput sequencing technology. SynCom inoculation significantly increased shoot height, stem diameter, fresh weight, dry weight, chlorophyll content, leaf number, root vigor, root tips, total root length, and root-specific surface area of pepper by 20.9%, 36.33%, 68.84%, 64.34%, 29.65%, 27.78%, 117.42%, 35.4%, 21.52%, and 39.76%, respectively, relative to the control. The Chao index of the rhizosphere microbial community and Bray–Curtis dissimilarity of the fungal community significantly increased, while Bray–Curtis dissimilarity of the bacterial community significantly decreased by SynCom inoculation. The abundances of key taxa such as Scedosporium, Sordariomycetes, Pseudarthrobacter, norankSBR1031, and norankA4b significantly increased with SynCom inoculation, and positively correlated with indices of pepper growth. Our findings suggest that SynCom inoculation can effectively enhance pepper growth and regulate root morphology by regulating rhizosphere microbial communities and increasing key taxa abundance like Sordariomycetes and Pseudarthrobacter, thereby benefiting nutrient acquisition, resistance improvement, and pathogen resistance of crops to ensure sustainability.

Light quality and intensity can have a significant impact on plant health and crop productivity. Chlorophylls and carotenoids are classes of plant pigments that are responsible for harvesting light energy and protecting plants from the damaging effects of intense light. Our understanding of the role played by plant pigments in light sensitivity has been aided by light-sensitive mutants that change colors upon exposure to light of variable intensity. In this study, we conducted transcriptomic, metabolomic, and hormone analyses on a novel yellowing mutant of pepper (yl1) to shed light on the molecular mechanism that regulates the transition from green to yellow leaves in this mutant upon exposure to high-intensity light. Our results revealed greater accumulation of the carotenoid precursor phytoene and the carotenoids phytofluene, antheraxanthin, and zeaxanthin in yl1 compared with wild-type plants under high light intensity. A transcriptomic analysis confirmed that enzymes involved in zeaxanthin and antheraxanthin biosynthesis were upregulated in yl1 upon exposure to high-intensity light. We also identified a single bHLH transcription factor, bHLH71-like, that was differentially expressed and positively correlated with light intensity in yl1. Silencing of bHLH71-like in pepper plants suppressed the yellowing phenotype and led to reduced accumulation of zeaxanthin and antheraxanthin. We propose that the yellow phenotype of yl1 induced by high light intensity could be caused by an increase in yellow carotenoid pigments, concurrent with a decrease in chlorophyll accumulation. Our results also suggest that bHLH71-like functions as a positive regulator of carotenoid biosynthesis in pepper.