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Meprin and TRAF homology (MATH)-domain-containing proteins are pivotal in modulating plant development and environmental stress responses. To date, members of the MATH gene family have been identified only in a few plant species, including Arabidopsis thaliana, Brassica rapa, maize, and rice, and the functions of this gene family in other economically important crops, especially the Solanaceae family, remain unclear. The present study identified and analyzed 58 MATH genes from three Solanaceae species, including tomato (Solanum lycopersicum), potato (Solanum tuberosum), and pepper (Capsicum annuum). Phylogenetic analysis and domain organization classified these MATH genes into four groups, consistent with those based on motif organization and gene structure. Synteny analysis found that segmental and tandem duplication might have contributed to MATH gene expansion in the tomato and the potato, respectively. Collinearity analysis revealed high conservation among Solanaceae MATH genes. Further cis-regulatory element prediction and gene expression analysis showed that Solanaceae MATH genes play essential roles during development and stress response. These findings provide a theoretical basis for other functional studies on Solanaceae MATH genes. [ABSTRACT FROM AUTHOR]

Plants produce diverse secondary compounds as natural protection against microbial and insect attack. Most of these compounds, including bitters and acids, are sensed by insect gustatory receptors (Grs). Although some organic acids are attractive at low or moderate levels, most acidic compounds are potentially toxic to insects and repress food consumption at high concentrations. At present, the majority of the reported sour receptors function in appetitive behaviors rather than aversive taste responses. Here, using two different heterologous expression systems, the insect Sf9 cell line and the mammalian HEK293T cell line, we started from crude extracts of rice (Oryza sativa) and successfully identified oxalic acid (OA) as a ligand of NlGr23a, a Gr in the brown planthopper Nilaparvata lugens that feeds solely on rice. The antifeedant effect of OA on the brown planthopper was dose dependent, and NlGr23a mediated the repulsive responses to OA in both rice plants and artificial diets. To our knowledge, OA is the first identified ligand of Grs starting from plant crude extracts. These findings on rice–planthopper interactions will be of broad interest for pest control in agriculture and also for better understanding of how insects select host plants. [ABSTRACT FROM AUTHOR]

Rice blast, caused by the fungus Magnaporthe oryzae, is the most devastating fungal disease of rice. Mowanggu, a local japonica cultivar in Yunnan Province, China, confers broad-spectrum resistance to this pathogen. To identify the resistance gene(s) in Mowanggu, we obtained an F population and 280 F recombinant inbred lines (RILs) from a cross between Mowanggu and CO39, a highly susceptible indica cultivar. A linkage map with 145 simple sequence repeat (SSR) and single feature polymorphism markers over 12 chromosomes was constructed using the 280 RILs. The resistance evaluation of the F and F populations in both the growth chamber and in a natural rice blast nursery showed that a single dominant gene controls blast resistance in Mowanggu. Moreover, nine quantitative trait loci, which were responsible for different partial resistance components, were mapped on chromosomes 2, 3, 6, 8, 9, and 12, making contributions to the phenotypic variation ranging from 3.03 to 6.18 %. The dominant resistance gene, designated Pi49, was mapped on chromosome 11 with genetic distance of 1.01 and 1.89 cM from SSR markers K10 and K134, respectively. The physical distance between K10 and K134 is about 181 kb in the Nipponbare genome. The Pi49 gene accounted for the major phenotypic variation of disease severity in the growth chamber (where plants were inoculated with single blast isolates) and also accounted for most of the phenotypic variance of disease severity, lesion number, diseased leaf area, and lesion size in the blast nursery. Our study not only identified tightly linked markers for introgression of Pi49 into elite rice cultivars via marker-aided selection but also provides a starting point for map-based cloning of the new resistance gene. [ABSTRACT FROM AUTHOR]

Multidrug and Toxic Compound Extrusion (MATE) proteins are essential transporters that extrude metabolites and participate in plant development and the detoxification of toxins. Little is known about the MATE gene family in the Solanaceae, which includes species that produce a broad range of specialized metabolites. Here, we identified and analyzed the complement of MATE genes in pepper (Capsicum annuum) and potato (Solanum tuberosum). We classified all MATE genes into five groups based on their phylogenetic relationships and their gene and protein structures. Moreover, we discovered that tandem duplication contributed significantly to the expansion of the pepper MATE family, while both tandem and segmental duplications contributed to the expansion of the potato MATE family, indicating that MATEs took distinct evolutionary paths in these two Solanaceous species. Analysis of ω values showed that all potato and pepper MATE genes experienced purifying selection during evolution. In addition, collinearity analysis showed that MATE genes were highly conserved between pepper and potato. Analysis of cis-elements in MATE promoters and MATE expression patterns revealed that MATE proteins likely function in many stages of plant development, especially during fruit ripening, and when exposed to multiple stresses, consistent with the existence of functional differentiation between duplicated MATE genes. Together, our results lay the foundation for further characterization of pepper and potato MATE gene family members. [ABSTRACT FROM AUTHOR]

Membrane Attack Complex and Perforin (MACPF) proteins play crucial roles in plant development and plant responses to environmental stresses. To date, only four MACPF genes have been identified in Arabidopsis thaliana, and the functions of the MACPF gene family members in other plants, especially in important crop plants, such as the Poaceae family, remain largely unknown. In this study, we identified and analyzed 42 MACPF genes from six completely sequenced and well annotated species representing the major Poaceae clades. A phylogenetic analysis of MACPF genes resolved four groups, characterized by shared motif organizations and gene structures within each group. MACPF genes were unevenly distributed along the Poaceae chromosomes. Moreover, segmental duplications and dispersed duplication events may have played significant roles during MACPF gene family expansion and functional diversification in the Poaceae. In addition, phylogenomic synteny analysis revealed a high degree of conservation among the Poaceae MACPF genes. In particular, Group I, II, and III MACPF genes were exposed to strong purifying selection with different evolutionary rates. Temporal and spatial expression analyses suggested that Group III MACPF genes were highly expressed relative to the other groups. In addition, most MACPF genes were highly expressed in vegetative tissues and up-regulated by several biotic and abiotic stresses. Taken together, these findings provide valuable information for further functional characterization and phenotypic validation of the Poaceae MACPF gene family. [ABSTRACT FROM AUTHOR]