摘要：
IntroductionSecondary metabolites are important compounds in plants to resist stress, deter herbivores, and prevent attack from some pathogens (Tewksbury et al., 2008). It is clear that plants have evolved their own special secondary metabolites on the basis of adaptations to the surrounding environment. Amongst these, the unique defensive chemical compounds produced by Capsicum, including capsaicin (CAP), dihydrocapsaicin (DhCAP), and several analogs, collectively known as capsaicinoids (CAPDs), are the most widely involved (Stewart et al., 2007). It is also known that CAPDs, unique flavoring substances in chili peppers, make peppers spicy but also influence the synthesis and accumulation of volatile aroma substances (Aza-González et al., 2011). In addition to self-protection, CPADs are also widely applied across industries including food, pharmaceuticals, and medical areas (Naves et al., 2019). Thus, regarding CPAD biosynthetic pathways, CAP and DhCAP account for nearly 90% in pepper species, divided into phenylpropanoid and branched chain fatty acid pathways (Choi et al., 2006). One specific approach is to synthesize capsaicin by condensing vanillylamine molecules and to derive this compound from phenylalanine via branched chain fatty acids (between nine and 11 carbon atoms), themselves synthesized from either valine or leucine (Arce-Rodriguez and Ochoa-Alejo, 2019). Indeed, as sequencing technology has developed, studies have revealed that Capsicum fruit biosynthesis i...
通讯机构：
[Fei, ZJ ; Wu, S] B;[Zou, XX ] H;Hunan Agr Univ, Coll Hort, Engn Res Ctr Germplasm Innovat & New Varieties Bre, Key Lab Vegetable Biol Hunan Prov, Changsha, Peoples R China.;Boyce Thompson Inst Plant Res, Ithaca, NY USA.;USDA Agr Res Serv, Robert W Holley Ctr Agr & Hlth, Ithaca, NY 14853 USA.
摘要：
Pepper (Capsicum spp.) is one of the earliest cultivated crops and includes five domesticated species, C. annuum var. annuum, C. chinense, C. frutescens, C. baccatum var. pendulum and C. pubescens. Here, we report a pepper graph pan-genome and a genome variation map of 500 accessions from the five domesticated Capsicum species and close wild relatives. We identify highly differentiated genomic regions among the domesticated peppers that underlie their natural variations in flowering time, characteristic flavors, and unique resistances to biotic and abiotic stresses. Domestication sweeps detected in C. annuum var. annuum and C. baccatum var. pendulum are mostly different, and the common domestication traits, including fruit size, shape and pungency, are achieved mainly through the selection of distinct genomic regions between these two cultivated species. Introgressions from C. baccatum into C. chinense and C. frutescens are detected, including those providing genetic sources for various biotic and abiotic stress tolerances.
摘要：
The transcription factors, B-box (BBX), belong to a subfamily of the zinc finger family of proteins and exhibit multiple biological functions in plant growth, development, and abiotic stress response pathways. In this study, a total of 23 CaBBX members were identified using the pepper reference genome database. According to the gene structure, conserved domains, and the phylogenetic tree, 23 CaBBX genes were divided into four groups, wherein the analysis of the promoter region indicated the presence of cis-acting elements related to plant development, hormones, and stress response. Interspecies collinearity analysis showed that the CaBBXs had three duplicated gene pairs, and the highest gene density was found on chromosomes 2 and 7. Transcriptome RNA-seq data and quantitative polymerase chain reaction (qRT-PCR) analysis of pepper plants spanning the entire period showed that more than half of the CaBBX genes were widely expressed in diversity tissues of pepper. Co-expression network analysis indicated that the CaBBXs and the anthocyanin structural genes had a close co-expression relationship. Thus, it was reasonably speculated that the CaBBX genes may be involved in the regulation of anthocyanin biosynthesis. Overall, this study involved the genome-wide characterization of the CaBBX family and may serve as a solid foundation for further investigations on CaBBX genes involved in the anthocyanin synthesis mechanisms and development in pepper.
通讯机构：
[Feng Liu; Xuexiao Zou] A;Authors to whom correspondence should be addressed.<&wdkj&>Key Laboratory for Vegetable Biology of Hunan Province, Engineering Research Center for Germplasm Innovation and New Varieties Breeding of Horticultural Crops, College of Horticulture, Hunan Agricultural University, Changsha 410125, China<&wdkj&>Longping Branch, Graduate School of Hunan University, Changsha 410125, China
摘要：
Chili pepper is an important economic vegetable worldwide. MYB family gene members play an important role in the metabolic processes in plant growth and development. In this study, 103 pepper MYB-related members were identified and grouped into nine subfamilies according to phylogenetic relationships. Additionally, a total of 80, 20, and 37 collinear gene pairs were identified between pepper and tomato, pepper and Arabidopsis, and tomato and Arabidopsis, respectively. We performed promoter cis-element analysis and showed that CaMYB-related members may be involved in multiple biological processes such as growth and development, secondary metabolism, and circadian rhythm regulation. Expression pattern analysis indicated that CaMYB37 is significantly more enriched in fruit placenta, suggesting that this gene may be involved in capsaicin biosynthesis. Through VIGS, we confirmed that CaMYB37 is critical for the biosynthesis of capsaicin in placenta. Our subcellular localization studies revealed that CaMYB37 localized in the nucleus. On the basis of yeast one-hybrid and dual-luciferase reporter assays, we found that CaMYB37 directly binds to the promoter of capsaicin biosynthesis gene AT3 and activates its transcription, thereby regulating capsaicin biosynthesis. In summary, we systematically identified members of the CaMYB-related family, predicted their possible biological functions, and revealed that CaMYB37 is critical for the transcriptional regulation of capsaicin biosynthesis. This work provides a foundation for further studies of the CaMYB-related family in pepper growth and development.
作者机构：
[刘峰; 杨博智; 熊程; 刘周斌; 邹学校; 徐昊; 戴雄泽; 胡博文; 欧立军; 远方; 索欢] College of Horticulture, Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, Hunan Agricultural University, Changsha, 410128, China;[朱凡] College of Landscape Architecture and Art Design, Hunan Agricultural University, Changsha, 410128, China
摘要：
Catalases (CATs) break down hydrogen peroxide into water and oxygen to prevent cellular oxidative damage, and play key roles in the development, biotic and abiotic stresses of plants. However, the evolutionary relationships of the plant CAT gene family have not been systematically reported. Here, we conducted genome-wide comparative, phylogenetic, and structural analyses of CAT orthologs from 29 out of 31 representative green lineage species to characterize the evolution and functional diversity of CATs. We found that CAT genes in land plants were derived from core chlorophytes and detected a lineage-specific loss of CAT genes in Fabaceae, suggesting that the CAT genes in this group possess divergent functions. All CAT genes were split into three major groups (group α, β1, and β2) based on the phylogeny. CAT genes were transferred from bacteria to core chlorophytes and charophytes by lateral gene transfer, and this led to the independent evolution of two types of CAT genes: α and β types. Ten common motifs were detected in both α and β groups, and β CAT genes had five unique motifs, respectively. The findings of our study are inconsistent with two previous hypotheses proposing that (i) new CAT genes are acquired through intron loss and that (ii) the Cys-343 residue is highly conserved in plants. We found that new CAT genes in most higher plants were produced through intron acquisition and that the Cys-343 residue was only present in monocots, Brassicaceae and Pp_CatX7 in P. patens, which indicates the functional specificity of the CATs in these three lineages. Finally, our finding that CAT genes show high overall sequence identity but that individual CAT genes showed developmental stage and organ-specific expression patterns suggests that CAT genes have functionally diverged independently. Overall, our analyses of the CAT gene family provide new insights into their evolution and functional diversification in green lineage species.
作者机构：
[邹学校] Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China;[朱凡] College of Landscape Architecture and Art Design, Hunan Agricultural University, Changsha, 410128, China
通讯机构：
[Zou, X.] E;Engineering Research Center of Education Ministry for Germplasm Innovation and Breeding New Varieties of Horticultural Crops, College of Horticulture, Hunan Agricultural University, Changsha, China
通讯机构：
[Zou, X.] L;[Qin, C.] E;Engineering Research Center of Zunyi Pepper Germplasm Resources Conservation and Breeding Cultivation of Guizhou Province, China;Longping Branch, China
摘要：
Ovate family proteins (OFPs) are transcriptional inhibitors that regulate plant growth and development and play important roles in the synthesis of secondary cell walls during pollen development. This study identified the pepper OFP gene family based on the genome-wide analysis and used bioinformatics methods to provide a fundamental profile of the gene family. 74 OFP genes with typical Ovate domain were identified in cultivated pepper Zunla-1, wild pepper Chiltepin and CM334. Chromosome mapping revealed that CazOFP genes were unevenly distributed on 11 chromosomes and Chr00 in Zunla-1, CacOFP genes on 12 chromosomes in Chiltepin, and CamOFP genes on 12 chromosomes and two Scaffflods in CM334. Gene structure analysis revealed that CaOFP genes possessed 1-3 exons, and the analysis of physicochemical properties suggested that CaOFPs were hydrophilic. Many cis-acting elements were identified in the promoter region of CaOFP genes, including ABRE, ARE, Box 4, G-box, TC-rich, and TCT-motif. The expression patterns of pepper at different growth stages showed that CaOFP genes were actively involved in the growth and fruit development of pepper, and CazOFP16 and CazOFP17 were actively involved in response to multiple hormones and stress events. qRT-PCR was also used to verify the expression of CazOFP gene in two developmental stages of seven pepper varieties with different fruit shapes, and it was found that CaOFP genes may be involved in the formation of fruit type in pepper. This study provides theoretical and practical evidence for future research on the OFP gene family.
通讯机构：
Eng. Res. Ctr. of Educ. Min. for Germplasm Innov. and Breeding New Varieties of Horticultural Crops, College of Horticulture, Hunan Agricultural University, Changsha, China
摘要：
Dear Editor, Pepper (C. annuum L.) is an important vegetable crop worldwide [1], with remarkable diversity in morphology, nutrition, color, flavor, and yield. A great effort has been made to identify quantitative trait loci (QTLs) and genes that affect these traits [2, 3]. However, few effective combinatorial events in small population sizes have limited the mapping of high-confidence QTLs for markerassisted breeding (MAB) and map-based gene cloning. The combined multi-omics approach has provided powerful tools for the rapid mining of candidate genes for MAB and for improving our understanding of candidate genes and their molecular regulation [4, 5].
作者机构：
[赵凯; Lü J.; 王梓然; 张祥; 张芮豪; 刘雨婷; 谢志和] Vegetable Seed Industry Engineering Research Center for the Universities of Yunnan Province, College of Landscape and Horticulture, Yunnan Agricultural University, Kunming, 650201, China;Institute of Sericulture and Apiculture, Yunnan Academy of Agricultural Sciences, Yunnan, Mengzi, 661101, China;[文锦芬] Kunming University of Science and Technology, Kunming, 650500, China;[邹学校] Hunan Agricultural University, Changsha, 410128, China;Deng Minghua Expert Basic Scientific Research Workstation of Yuxi City, Economic Crop Workstation of Tonghai County, Tonghai, Yunnan, 652700, China
通讯机构：
[Wen, J.] K;[Zou, X.] H;[Deng, M.] V;Hunan Agricultural UniversityChina;Vegetable Seed Industry Engineering Research Center for the Universities of Yunnan Province, China
