Self-incompatibility (SI) is a widespread and important mating system that promotes outcrossing in plants. Erigeron breviscapus, a medicinal herb used widely in traditional Chinese medicine, is a self-incompatible species of Asteraceae. However, the genetic characteristics of SI responses in E. breviscapus remain largely unknown. To understand the possible mechanisms of E. breviscapus in response to SI, we performed a comparative transcriptomic analysis with capitulum of E. breviscapus after self- and cross-pollination, which may provide valuable information for analyzing the candidate SI-associated genes of E. breviscapus. Using a high-throughput next-generation sequencing (Illumina) approach, the transcriptionexpression profiling of the different genes of E. breviscapus were obtained, some results were verified by quantitative real time PCR (qRT-PCR). After assembly, 63,485 gene models were obtained (average gene size 882 bp; N50 = 1485 bp), among which 38,540 unigenes (60.70 % of total gene models) were annotated by comparisons with four public databases (Nr, Swiss-Prot, KEGG and COG): 38,338 unigenes (60.38 % of total gene models) showed high homology with sequences in the Nr database. Differentially expressed genes were identified among the three cDNA libraries (non-, self- and cross-pollinated capitulum of E. breviscapus), and approximately 230 genes might be associated with SI responses. Several these genes were upregulated in self-pollinated capitulum but downregulated in cross-pollinated capitulum, such as SRLK (SRK-like) and its downstream signal factor, MLPK. qRT-PCR confirmed that the expression patterns of EbSRLK1 and EbSRLK3 genes were not closely related to SI of E. breviscapus. This work represents the first large-scale analysis of gene expression in the self-pollinated and cross-pollinated flowers of E. breviscapus. A larger number of notable genes potentially involved in SI responses showed differential expression, including genes playing crucial roles in cell-cell communication, signal transduction and the pollination process. We thus hypothesized that those genes showing differential expression and encoding critical regulators of SI responses, such as MLPK, ARC1, CaM, Exo70A1, MAP, SF21 and Nod, might affect SI responses in E. breviscapus. Taken together, our study provides a pool of SI-related genes in E. breviscapus and offers a valuable resource for elucidating the mechanisms of SI in Asteraceae.

The MADS-box gene family encodes transcription factors with many biological functions that extensively regulate plant growth, development and reproduction. Erigeron breviscapus is a medicinal herb used widely in traditional Chinese medicine, and is believed to improve blood circulation and ameliorate platelet coagulation. In order to gain a detailed understanding of how transcription factor expression may regulate the growth of this potentially important medicinal plant, a genome-wide analysis of the MADS-box gene family of E. breviscapus is needed. In the present study, 44 MADS-box genes were identified in E. breviscapus and categorized into five subgroups (MIKC, Mα, Mβ, Mγ and Mδ) according to their phylogenetic relationships with the Arabidopsis MADS-box genes. Additionally, the functional domain, subcellular location and motif compositions of the E. breviscapus MADS-box gene products were characterized. The expression levels for each of the E. breviscapus MADS-box (EbMADS) genes were analyzed in flower, leaf, stem and root organs, and showed that the majority of EbMADS genes were expressed in flowers. Meanwhile, some MADS genes were found to express high levels in leaf, stem and root, indicating that the MADS-box genes are involved in various aspects of the physiological and developmental processes of the E. breviscapus. The results from gene expression analysis under different pollination treatments revealed that the MADS-box genes were highly expressed after non-pollinated treatment. To the best of our knowledge, this study describes the first genome-wide analysis of the E. breviscapus MADS-box gene family, and the results provide valuable information for understanding of the classification, cloning and putative functions of the MADS-box family.

Cell walls play an important role in the structure and morphology of plants as well as in responses to various biotic and abiotic stresses. Although the comprehensive analysis of genes involved in cellulose synthase has been performed in model...

Erigeron breviscapus (Vant.) Hand.-Mazz. is a famous traditional Chinese medicine that has positive effects on the treatment of cardiovascular and cerebrovascular diseases. With the increase of market demand (RMB 500 million per year) and the sharp decrease of wild resources, it is an urgent task to cultivate high-quality and high-yield varieties of E. breviscapus. However, it is difficult to obtain homozygous lines in breeding due to the self-incompatibility (SI) of E. breviscapus. Here, we first proved that E. breviscapus has sporophyte SI (SSI) characteristics. Characterization of the ARC1 gene in E. breviscapus showed that EbARC1 is a constitutive expression gene located in the nucleus. Overexpression of EbARC1 in Arabidopsis thaliana L. (Col-0) could cause transformation of transgenic lines from self-compatibility (SC) into SI. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays indicated that EbARC1 and EbExo70A1 interact with each other in the nucleus, and the EbARC1-ubox domain and EbExo70A1-N are the key interaction regions, suggesting that EbARC1 may ubiquitinate EbExo70A to regulate SI response. This study of the SSI mechanism in E. breviscapus has laid the foundation for further understanding SSI in Asteraceae and breeding E. breviscapus varieties.

The Honghe Hani Rice Terraces System (HHRTS) of Yunnan Province is an important agricultural and cultural heritage landscape. Until now, a large number of local rice landraces have been planted. Mining excellent genes contained in these landraces provides a reference for variety improvement and new variety breeding. In this study, 96 rice landraces collected from the Hani terraces were planted in Honghe Mengzi, Yunnan Province, in 2013, 2014, 2015, and 2021, and five major grain traits were measured and analyzed. The genomic variation of 96 rice landraces was scanned by 201 simple sequence repeat (SSR) markers. The genetic diversity, population structure, and genetic relationships of the natural population were analyzed. The mixed linear model (MLM) method of the TASSEL software was used to analyze the associations between markers and traits. A total of 936 alleles were amplified by 201 pairs of SSR primers. The average number of observed alleles (Na), the effective number of alleles (Ne), Shannon’s information index (I), heterozygosity (H), and the polymorphism information content (PIC) per marker were 4.66, 2.71, 1.08, 0.15, and 0.55, respectively. Ninety-six landraces were divided into two groups by population structure, clustering, and principal component analysis, and indica rice was the main group. The coefficients of variation of the five traits ranged from 6.80 to 15.24%, and their broad heritabilities were more than 70%. In addition, there were positive correlations among the same grain traits between different years. Through MLM analysis, 2, 36, 7, 7, and 4 SSR markers were significantly associated with grain length (GL), grain width (GW), grain thickness (GT), grain length–width ratio (LWR), and thousand-grain weight (TGW), respectively. The explanation rates of phenotypic variation were 16.31 (RM449, Chr. 1)—23.51% (RM316, Chr. 9), 10.84 (RM523, Chr. 3; RM161/RM305, Chr. 5)—43.01% (RM5496, Chr. 1), 11.98 (RM161/RM305, Chr. 5)—24.72% (RM275, Chr. 6), 12.68 (RM126, Chr. 8)—36.96% (RM5496, Chr. 1), and 17.65 (RM4499, Chr. 2)—26.32% (RM25, Chr. 8), respectively. The associated markers were distributed on 12 chromosomes of the genome.