SUMMARYReceptor‐like cytoplasmic kinases (RLCKs) mediate the intracellular signaling downstream of pattern‐recognition receptors (PRRs). Several RLCKs from subfamily VII of rice (Oryza sativa) have important roles in plant immunity, but the role of RLCK VII‐4 in pattern‐triggered immune (PTI) signaling and resistance to pathogens has not yet been investigated. Here, we generated by multiplex clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR‐associated protein 9‐mediated genome editing rice sextuple mutant lines where the entire RLCK VII‐4 subfamily is inactivated and then analyzed the resulting lines for their response to chitin and flg22 and for their immunity to Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae. Analysis of the rlckvii‐4 mutants revealed that they have an impaired reactive oxygen system burst and reduced defense gene expression in response to flg22 and chitin. This indicates that members of the rice RLCK VII‐4 subfamily are required for immune signaling downstream of multiple PRRs. Furthermore, we found that the rice RLCK VII‐4 subfamily is important for chitin‐induced callose deposition and mitogen‐activated protein kinase activation and that it is crucial for basal resistance against Xoo and M. oryzae pathogens. This establishes that the RLCK VII‐4 subfamily has critical functions in the regulation of multiple PTI pathways in rice and opens the way for deciphering the precise role of its members in the control of rice PTI.
Annexins (Anns) play an important role in plant development, growth and responses to various stresses. Although Ann genes have been characterized in some plants, their role in adaptation mechanisms and tolerance to environmental stresses have not been studied in extremophile plants. In this study, Ann genes in Schrenkiella parvula and Eutrema salsugineum were identified using a genome-wide method and phylogenetic relationships, subcellular distribution, gene structures, conserved residues and motifs and also promoter prediction have been studied through bioinformatics analysis. We identified ten and eight encoding putative Ann genes in S. parvula and E. salsugineum genome respectively, which were divided into six subfamilies according to phylogenetic relationships. By observing conservation in gene structures and protein motifs we found that the majority of Ann members in two extremophile plants are similar. Furthermore, promoter analysis revealed a greater number of GATA, Dof, bHLH and NAC transcription factor binding sites, as well as ABRE, ABRE3a, ABRE4, MYB and Myc cis-acting elements in compare to Arabidopsis thaliana. To gain additional insight into the putative roles of candidate Ann genes, the expression of SpAnn1, SpAnn2 and SpAnn6 in S. parvula was studied in response to salt stress, which indicated that their expression level in shoot increased. Similarly, salt stress induced expression of EsAnn1, 5 and 7, in roots and EsAnn1, 2 and 5 in leaves of E. salsugineum. Our comparative analysis implies that both halophytes have different regulatory mechanisms compared to A. thaliana and suggest SpAnn2 gene play important roles in mediating salt stress.
Background: Datura species produce a wide range of tropane alkaloids with medicinal values. D. innoxia is a species of the Datura genus which is poisonous and has an unpleasant odor due to the presence of tropane alkaloids. Objective: The study aimed to induction of polyploidy by colchicine treatment on downy thorn-apple and the effect of it on appearance and hyoscyamine content. Methods: In order to induce tetraploidy in downy thorn-apple, a factorial experiment was carried out with two factors: colchicine concentrations (0.05, 0.1, and 0.2 %) and exposure time (48 and 72 h) with 3 plants for each treatment with using a cotton ball included colchicine on shoot tip. Morphological changes were observed and the plants were analyzed by flow cytometry in near to the flowering time. Results: The results showed that the concentration and exposure time of colchicine, and their interaction affected the percentage of tetraploidy. The maximum percent of tetraploidy was observed in concentration of 0.2 % and 72 h. On the other hand, the application of different concentrations of colchicine and exposure time didn't have a significant effect on plant survival. The number of stomatal guard cells were decreased but no significant differences were observed in the content of total chlorophyll and carotenoids. Also, the hyoscyamine content in tetraploid plants was decreased to half in comparison to diploid ones. Conclusion: In general, induction of tetraploidy in this plant could change some phenotypic traits but has a negative effect on hyoscyamine content.
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