Entang Tian

The development of biological control strategies for disease prevention and management is essential for sustainable agriculture. However, the lack of an effective screening system for biofumigant activities has notably hindered their widespread application. In the present study, we established an effective screening system for assessing biofumigant activities against Sclerotinia sclerotiorum , which was subsequently validated in mustard ( Brassica juncea L.) lines. Among the mustard lines examined, the predominant individual glucosinolates (GSLs) identified were 2-propenyl (allyl) and 3-butenyl (butyl) GSLs. Notably, allyl GSLs exhibited nearly double the biofumigant activity compared with butyl GSLs. Furthermore, the total GSLs demonstrated a stronger correlation with biofumigant activities in these mustard lines, leading to the development of a rapid determination approach utilizing the palladium chloride method as a primary screening indicator. In response to the biofumigant activities derived from mustard, the mycelial growth of S. sclerotiorum was significantly inhibited. Furthermore, seven hub genes in S. sclerotiorum were identified by RNA sequencing analysis. This study not only established an effective screening system for biofumigant activities against S. sclerotiorum but also explored the underlying mechanisms, which may facilitate the broader promotion and application of biofumigation methods in the future.

The regulatory mechanisms governing the biosynthesis of dietary fibers in the leaves and stems of mustard (Brassica juncea L.) have not been adequately characterized. Through quantitative trait locus (QTL) mapping, 23 consensus QTLs associated with dietary fiber content in rapidly growing leaves and stems were identified, highlighting Bju .CESA6.A01 as a Key Candidate Gene. Functional validation through overexpression of Bju .CESA6.A01 in Arabidopsis thaliana led to a significant 22.07% increase in the primary dietary fiber component, neutral detergent fiber. This enhancement was accompanied by increases in the number of vascular bundles, vascular bundle area, and proportion of vascular bundle area in stems. Additionally, 12 novel genes associated with Bju .CESA6.A01 was identified. These findings provide valuable insights into the genetic regulation of dietary fiber biosynthesis in mustard leaves and stems during their rapid growth phase.

Sclerotinia sclerotiorum could cause significant yield losses of up to 70% in rapeseed cultivation. Nevertheless, the availability of immune or highly resistant germplasm and mechanisms to combat S. sclerotiorum, particularly in B. juncea, remains insufficient. Transcription factors (TFs) are recognized for their critical role in plant defense against S. sclerotiorum. In the present study, a total of 4807 TFs from 48 families were expressed and identified at 12, 24, and 36 h after inoculation (HAI) in two B. juncea lines: G21-912, exhibiting higher S. sclerotiorum resistance (HR), and G21-853, displaying lower S. sclerotiorum resistance (LR). The number of differentially expressed TFs (DETs) between the HR and the LR lines peaked at 24 HAI, with 202 upregulated and 105 downregulated TFs. Through expression and subcellular localization analyses, three candidate DETs, namely BjuA037408 (ETHYLENE RESPONSIVE FACTOR 59, ERF59), BjuB028842 (RELATED TO ABI3/VP1 1, RAV1), and BjuA016484 (WRKY25), were identified as the primary TFs in defense against S. sclerotiorum inoculation. The expression of these three genes was validated in the double haploid lines of BC₃ (the third backcrossing generation) derived from the HR×LR cross. This study serves as a valuable case study for the characterization of TFs associated with defense mechanisms against S. sclerotiorum in B. juncea. The confirmed resistant B. juncea line of HR, along with the three key DETs, is expected to significantly contribute to future breeding efforts aimed at developing Sclerotinia-resistant varieties.

The use of a male sterility hybrid seed production system has resulted in a significant increase in rapeseed yields by over 20%. Nevertheless, the mechanisms underlying male sterility remain largely unexamined. This study presents a spontaneous recessive genic male-sterile (RGMS) mutant of 1205A, which was employed to establish two two-line hybrid production systems: 1205AB and NT7G132AB. Cytological investigations reveal that the mutation occurs at the early microspore stage, resulting in premature degradation of pollen. Through inheritance analysis, linkage mapping, and bulked-segregant analysis sequencing (BSA-Seq), a single gene locus, designated Bna1205ams1, was identified within the QTL region on chrC03 (15.36–18.90 Mb). The development of three newly co-segregated kompetitive allele-specific PCR (KASP) markers, in conjunction with two traditional co-segregated markers, allowed for the refinement of the QTL of Bna1205ams1 to a segment of 181.47 kb. This refinement facilitated the identification of a candidate gene, BnaC03g27700D, through functional and expression analyses. Furthermore, the subcellular localization of BnaC03g27700D was examined. Metabolic fluctuations associated with the fertility gene were observed, particularly in processes related to aborted tapetal programmed cell death (PCD), which may contribute to reduced pollen fertility with abnormal pollen exine. A strong correlation was also established between BnaC03g27700D and thirteen metabolites. This study not only offers valuable insights into the research and practical application of plant male sterility but also serves as a case study on the genetic regulatory mechanisms governing male sterility.

Aims: The genic male sterility (GMS) system is an important strategy for generating heterosis in plants. To better understand the essential role of lipid and sugar metabolism and to identify additional candidates for pollen development and male sterility, transcriptome and metabolome analysis of a GMS line of 1205AB in B. napus was used as a case study.Data resources generated: To characterize the GMS system, the transcriptome and metabolome profiles were generated for 24 samples and 48 samples of 1205AB in B. napus, respectively. Transcriptome analysis yielded a total of 156.52 Gb of clean data and revealed the expression levels of 109,541 genes and 8,501 novel genes. In addition, a total of 1,353 metabolites were detected in the metabolomic analysis, including 784 in positive ion mode and 569 in negative ion mode.Key results: A total of 15,635 differentially expressed genes (DEGs) and 83 differential metabolites (DMs) were identified from different comparison groups, most of which were involved in lipid and sugar metabolism. The combination of transcriptome and metabolome analysis revealed 49 orthologous GMS genes related to lipid metabolism and 46 orthologous GMS genes related to sugar metabolism, as well as 45 novel genes.Utility of the resource: The transcriptome and metabolome profiles and their analysis provide useful reference data for the future discovery of additional GMS genes and the development of more robust male sterility breeding systems for use in the production of plant hybrids.

Through the comprehensive use of two pollination control systems of cytoplasmic male sterility (CMS) and genic male sterility (GMS), the rapeseed yield was increased by more than 20%. However, more hybrid production systems and detailed mechanisms underlying male sterility are required. Here, we reported a novel two-line hybrid production system of 1205A for GMS and also investigated the underlying mechanism for male sterility. Five co-segregated kompetitive allele specific PCR (KASP) markers were developed and validated, which could be used for transferring the male sterility trait into external B. napus breeding lines and developing further two-line hybrid production systems of GMS. Inheritance studies detected one gene locus of Bna1205ams1 for regulating the male sterility of 1205A. As a potential candidate gene of Bna1205ams1 , BnaC03g27700D was fine mapped and narrowed down to a 181.47 kb region on chrC03 and validated by functional analysis. The mutation of BnaC03g27700D in 1205A resulted in large metabolic fluctuations, most of which were involved in aborted tapetal PCD, which could lead to reduced pollen fertility with abnormal pollen exine. The developed new GMS line of 1205AB provided us with the opportunity to identify a new male sterility gene of BnaC03g27700D in B. napus . The study of BnaC03g27700D aims to renew the annotation of the gene and provide new resources for basic research on the genetic control of male sterility.

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum , is the main disease threat to oilseeds in Brassiceae, causing significant yield losses and reduction in oil content and quality. The studies on S. sclerotiorum require a great focus and extensive research on B. juncea compared to those on B. napus and B. oleracea . Transcriptome analysis revealed a large number of defense-related genes and response processes in B. napus and B. oleracea . However, similarities and differences in the defense responses to S. sclerotiorum on B. juncea are rarely reported. In the present study, we reported a B. juncea breeding line of H83 with high S. sclerotiorum resistance, which was used for transcriptome analysis compared to L36 with low resistance. A novel regulatory network was proposed to defend against S. sclerotiorum invasion in B. juncea . Upon infection of S. sclerotiorum , a series of auxin and MAPK signaling pathways were initiated within 12 h, and then defenses were activated to restrict the development and spread of S. sclerotiorum by inducing the massive synthesis of indole glucosinolates after 24 h. Twelve hub genes involved in the network were identified by the weighted gene co-expression network (WGCNA), which are involved in plant-pathogen interaction, signaling pathway genes, indole glucosinolate biosynthesis and cell wall formation. The hub genes were further validated by qRT-PCR. The research revealed a new resistant line of H83 against S. sclerotiorum and a different regulatory network in B. juncea , which would be beneficial for the future effective breeding of Sclerotinia-resistant varieties.

Protein prenylation mediated by the Arabidopsis thaliana PLURIPETALA (AtPLP) gene plays a crucial role in plant growth, development, and environmental response by adding a 15-carbon farnesyl group or one to two 20-carbon geranylgeranyl groups onto one to two cysteine residues at the C-terminus of the target protein. However, the homologous genes and their functions of AtPLP in rapeseed are unclear. In this study, bioinformatics analysis and gene cloning demonstrated the existence of two homologous genes of AtPLP in the Brassica napus L. genome, namely, BnPLP1 and BnPLP2. Evolutionary analysis revealed that BnPLP1 originated from the B. rapa L. genome, while BnPLP2 originated from the B. oleracea L. genome. Genetic transformation analysis revealed that the overexpression of BnPLP1 in Arabidopsis plants exhibited earlier flowering initiation, a prolonged flowering period, increased plant height, and longer main inflorescence length compared to the wild type. Contrarily, the downregulation of BnPLP1 expression in B. napus plants led to delayed flowering initiation, shortened flowering period, decreased plant height, and reduced main inflorescence length compared to the wild type. These findings indicate that the BnPLP1 gene positively regulates flowering time, plant height, and main inflorescence length. This provides a new gene for the genetic improvement of flowering time and plant architecture in rapeseed.