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Background: The receptor-like kinase (RLK) gene families in plants contains a large number of members. They are membrane proteins with an extracellular receptor domain and participate in biotic and abiotic stress responses. Results: In this study, we identified RLKs in 15 representative plant genomes, including wheat, and classified them into 64 subfamilies by using four types of phylogenetic trees and HMM models. Conserved exon‒intron structures with conserved exon phases in the kinase domain were found in many RLK subfamilies from Physcomitrella patens to Triticum aestivum. Domain distributions of RLKs were also diagrammed. Collinearity events and tandem gene clusters suggested that polyploidization and tandem duplication events contributed to the member expansions of T. aestivum RLKs. Global expression pattern analysis was performed by using public transcriptome data. These analyses were involved in T. aestivum, Aegilops tauschii and Brachypodium distachyon RLKs under biotic and abiotic stresses. We also selected 9 RLKs to validate the transcriptome prediction by using qRT‒PCR under drought treatment and with Fusarium graminearum infection. The expression trends of these 9 wheat RLKs from public transcriptome data were consistent with the results of qRT‒PCR, indicating that they might be stress response genes under drought or F. graminearum treatments. Conclusion: In this study, we identified, classified, evolved, and expressed RLKs in wheat and related plants. Thus, our results will provide insights into the evolutionary history and molecular mechanisms of wheat RLKs. [ABSTRACT FROM AUTHOR]

Foxtail millet (Setaria italica) is rich in nutrients and extremely beneficial to human health. We identified and comprehensively analyzed 89 MADS-box genes in the foxtail millet genome. According to the classification of MADS-box genes in Arabidopsis thaliana and rice, the SiMADS-box genes were divided into M-type (37) and MIKC-type (52). During evolution, the differentiation of MIKC-type MADS-box genes occurred before that of monocotyledons and dicotyledons. The SiMADS-box gene structure has undergone much differentiation, and the number of introns in the MIKC-type subfamily is much greater than that in the M-type subfamily. Analysis of gene duplication events revealed that MIKC-type MADS-box gene segmental duplication accounted for the vast majority of gene duplication events, and MIKC-type MADS-box genes played a major role in the amplification of SiMADS-box genes. Collinearity analysis showed highest collinearity between foxtail millet and maize MADS-box genes. Analysis of tissue-specific expression showed that SiMADS-box genes are highly expressed throughout the grain-filling process. Expression analysis of SiMADS-box genes under eight different abiotic stresses revealed many stress-tolerant genes, with induced expression of SiMADS33 and SiMADS78 under various stresses warranting further attention. Further, some SiMADS-box proteins may interact under external stress. This study provides insights for MADS-box gene mining and molecular breeding of foxtail millet in the future. [ABSTRACT FROM AUTHOR]

Background and aims: Conyza blinii is a unique traditional Chinese medicine growing in Sichuan, China, which has soils with an abundant iron content. This Fe-enriched environment contributes to a variety of terpenoids in C. blinii, such as blinin and saponin, which play an important role in the process of resisting abiotic stress. The relationship between Fe and terpenoid metabolism was studied to explore the Fe tolerance mechanism of C. blinii. Methods: In this study, C. blinii was treated with ferrous iron solutions, and the effect of ferrous iron on the synthesis of blinin and saponins was further studied by spectrophotometry and liquid chromatography. Additionally, gene expression was detected by qRT-PCR. Results: Under ferrous treatment, the blinin content of C. blinii increased, while the total saponin content decreased. When the ferrous concentration reached 200 μM, the difference in metabolite production was the largest. Furthermore, it was found that blinin and saponins have synchronous and opposite accumulation trends, characterized by time dependence. The gene expression results of key enzymes in the MVA and MEP pathways showed the same trends. In this process, the expression of CbNudixs played a key role in switching the material flux between MVA and MEP by catalyzing the dephosphorylation of isoprenoid diphosphate. Conclusions: In this study, it was found that under ferrous iron stimulation, the terpenoid content in C. blinii was different, and the metabolic pathways of MVA and MEP were periodically regulated. [ABSTRACT FROM AUTHOR]