aBIOTECH最新文献

Deoxynivalenol (DON) is a prominent mycotoxin showing significant accumulation in cereal plants during infection by the phytopathogen Fusarium graminearum. It is a virulence factor that is important in the spread of F. graminearum within cereal heads, and it causes serious yield losses and significant contamination of cereal grains. In recent decades, genetic and genomic studies have facilitated the characterization of the molecular pathways of DON biosynthesis in F. graminearum and the environmental factors that influence DON accumulation. In addition, diverse scab resistance traits related to the repression of DON accumulation in plants have been identified, and experimental studies of wheat–pathogen interactions have contributed to understanding detoxification mechanisms in host plants. The present review illustrates and summarizes the molecular networks of DON mycotoxin production in F. graminearum and the methods of DON detoxification in plants based on the current literature, which provides molecular targets for crop improvement programs. This review also comprehensively discusses recent advances and challenges related to genetic engineering-mediated cultivar improvements to strengthen scab resistance. Furthermore, ongoing advancements in genetic engineering will enable the application of these molecular targets to develop more scab-resistant wheat cultivars with DON detoxification traits.

Lipid droplets are important storages in fungal conidia and can be used by plant pathogenic fungi for infection. However, the regulatory mechanism of lipid droplets formation and the utilization during fungal development and infection are largely unknown. Here, in Magnaporthe oryzae, we identified a lipid droplet-associated protein Nem1 that played a key role in lipid droplets biogenesis and utilization. Nem1 was highly expressed in conidia, but lowly expressed in appressoria, and its encoded protein was localized to lipid droplets. Deletion of NEM1 resulted in reduced numbers of lipid droplets and decreased content of diacylglycerol (DAG) or triacylglycerol (TAG). NEM1 was required for asexual development especially conidia production. The Δnem1 mutant was nearly loss of virulence to host plants due to defects in appressorial penetration and invasive growth. Remarkably, Nem1 was regulated by the TOR signaling pathway and involved in the autophagy process. The Ser303 residue of Nem1 could be phosphorylated by the cAMP-PKA signaling pathway and was important for biological function of Nem1. Together, our study revealed a regulatory mechanism of lipid biogenesis and metabolism during the conidium and appressorium formation of the rice blast fungus.

Development of wheat (Triticum aestivum L.) grain mainly depends on the processes of starch synthesis and storage protein accumulation, which are critical for grain yield and quality. However, the regulatory network underlying the transcriptional and physiological changes of grain development is still not clear. Here, we combined ATAC-seq and RNA-seq to discover the chromatin accessibility and gene expression dynamics during these processes. We found that the chromatin accessibility changes are tightly associated with differential transcriptomic expressions, and the proportion of distal ACRs was increased gradually during grain development. Specific transcription factor (TF) binding sites were enriched at different stages and were diversified among the 3 subgenomes. We further predicted the potential interactions between key TFs and genes related with starch and storage protein biosynthesis and found different copies of some key TFs played diversified roles. Overall, our findings have provided numerous resources and illustrated the regulatory network during wheat grain development, which would shed light on the improvement of wheat yields and qualities.

The reproductive success of flowering plants, which directly affects crop yield, is sensitive to environmental changes. A thorough understanding of how crop reproductive development adapts to climate changes is vital for ensuring global food security. In addition to being a high-value vegetable crop, tomato is also a model plant used for research on plant reproductive development. Tomato crops are cultivated under highly diverse climatic conditions worldwide. Targeted crosses of hybrid varieties have resulted in increased yields and abiotic stress resistance; however, tomato reproduction, especially male reproductive development, is sensitive to temperature fluctuations, which can lead to aborted male gametophytes, with detrimental effects on fruit set. We herein review the cytological features as well as genetic and molecular pathways influencing tomato male reproductive organ development and responses to abiotic stress. We also compare the shared features among the associated regulatory mechanisms of tomato and other plants. Collectively, this review highlights the opportunities and challenges related to characterizing and exploiting genic male sterility in tomato hybrid breeding programs.

Rice produces many diterpenoid phytoalexins and, reflecting the importance of these natural products in this important cereal crop plant, its genome contains three biosynthetic gene clusters (BGCs) for such metabolism. The chromosome 4 BGC (c4BGC) is largely associated with momilactone production, in part due to the presence of the initiating syn-copalyl diphosphate (CPP) synthase gene (OsCPS4). Oryzalexin S is also derived from syn-CPP. However, the relevant subsequently acting syn-stemarene synthase gene (OsKSL8) is not located in the c4BGC. Production of oryzalexin S further requires hydroxylation at carbons 2 and 19 (C2 and C19), presumably catalyzed by cytochrome P450 (CYP) monooxygenases. Here it is reported the closely related CYP99A2 and CYP99A3, whose genes are also found in the c4BGC catalyze the necessary C19-hydroxylation, while the closely related CYP71Z21 and CYP71Z22, whose genes are found in the recently reported chromosome 7 BGC (c7BGC), catalyze subsequent hydroxylation at C2α. Thus, oryzalexin S biosynthesis utilizes two distinct BGCs, in a pathway cross-stitched together by OsKSL8. Notably, in contrast to the widely conserved c4BGC, the c7BGC is subspecies (ssp.) specific, being prevalent in ssp. japonica and only rarely found in the other major ssp. indica. Moreover, while the closely related syn-stemodene synthase OsKSL11 was originally considered to be distinct from OsKSL8, it has now been reported to be a ssp. indica derived allele at the same genetic loci. Intriguingly, more detailed analysis indicates that OsKSL8(j) is being replaced by OsKSL11 (OsKSL8i), suggesting introgression from ssp. indica to (sub)tropical japonica, with concurrent disappearance of oryzalexin S production.

Ever since the concept of “plant cell totipotency” was first proposed in the early twentieth century, plant regeneration has been a major focus of study. Regeneration-mediated organogenesis and genetic transformation are important topics in both basic research and modern agriculture. Recent studies in the model plant Arabidopsis thaliana and other species have expanded our understanding of the molecular regulation of plant regeneration. The hierarchy of transcriptional regulation driven by phytohormone signaling during regeneration is associated with changes in chromatin dynamics and DNA methylation. Here, we summarize how various aspects of epigenetic regulation, including histone modifications and variants, chromatin accessibility dynamics, DNA methylation, and microRNAs, modulate plant regeneration. As the mechanisms of epigenetic regulation are conserved in many plants, research in this field has potential applications in boosting crop breeding, especially if coupled with emerging single-cell omics technologies.

Plants are the most important sources of food for humans, as well as supplying many ingredients that are of great importance for human health. Developing an understanding of the functional components of plant metabolism has attracted considerable attention. The rapid development of liquid chromatography and gas chromatography, coupled with mass spectrometry, has allowed the detection and characterization of many thousands of metabolites of plant origin. Nowadays, elucidating the detailed biosynthesis and degradation pathways of these metabolites represents a major bottleneck in our understanding. Recently, the decreased cost of genome and transcriptome sequencing rendered it possible to identify the genes involving in metabolic pathways. Here, we review the recent research which integrates metabolomic with different omics methods, to comprehensively identify structural and regulatory genes of the primary and secondary metabolic pathways. Finally, we discuss other novel methods that can accelerate the process of identification of metabolic pathways and, ultimately, identify metabolite function(s).

Weeds cause tremendous economic and ecological damage worldwide. The number of genomes established for weed species has sharply increased during the recent decade, with some 26 weed species having been sequenced and de novo genomes assembled. These genomes range from 270 Mb (Barbarea vulgaris) to almost 4.4 Gb (Aegilops tauschii). Importantly, chromosome-level assemblies are now available for 17 of these 26 species, and genomic investigations on weed populations have been conducted in at least 12 species. The resulting genomic data have greatly facilitated studies of weed management and biology, especially origin and evolution. Available weed genomes have indeed revealed valuable weed-derived genetic materials for crop improvement. In this review, we summarize the recent progress made in weed genomics and provide a perspective for further exploitation in this emerging field.

Over time, wild crops have been domesticated by humans, and the knowledge gained from parallel selection and convergent domestication-related studies in cereals has contributed to current techniques used in molecular plant breeding. Sorghum (Sorghum bicolor (L.) Moench) is the world’s fifth-most popular cereal crop and was one of the first crops cultivated by ancient farmers. In recent years, genetic and genomic studies have provided a better understanding of sorghum domestication and improvements. Here, we discuss the origin, diversification, and domestication processes of sorghum based on archeological discoveries and genomic analyses. This review also comprehensively summarized the genetic basis of key genes related to sorghum domestication and outlined their molecular mechanisms. It highlights that the absence of a domestication bottleneck in sorghum is the result of both evolution and human selection. Additionally, understanding beneficial alleles and their molecular interactions will allow us to quickly design new varieties by further de novo domestication.

To ensure safe use of genetically modified organisms (GMOs), since 1993, China has made great efforts to establish and improve the safety regulatory system for GMOs. Here, we summarize and analyze the regulatory framework of agricultural GMOs, and the progress in regulatory approval of GM crops in China. In general, the development of GMO safety regulations underwent four stages: exploration (1993–2000), development (2001–2010), improvement (2011–2020) and current (2021-present) stage. The first formal regulation was promulgated in 1993, which provided a basis for further development of the regulations, during the exploration stage, when insect-resistant GM cotton, expressing genes from Bacillus thuringiensis (Bt), was approved for cultivation. During the development stage, the Chinese government issued a series of administrative measures, which covered almost all the fields relative to GMO safety when the basic regulatory system was established. Along with the controversy over GMO safety, the regulations have been further, and greatly improved, during improvement stage. From 2021, a few additional revisions have been made, and meanwhile, the new regulation on gene-edited crops was introduced with the development of biotechnology, forming a relative complete regulation and law system for China. The well-developed GMO regulations establishes a firm basis for safe use of GM crops in China. Currently, GM cotton and GM papaya have been widely grown on a large scale in China that have brought great economic and ecological benefits. In addition, 12 corn events, 3 soybean events, and 2 rice events have also obtained biosafety certification, but presently, these lines have yet to enter commercial production. However, several GM soybean and corn events have entered pilot industrialization, and can soon be expected to be commercially grown in China. In addition to planting, six GM crops, including soybean, corn, cotton, canola, papaya and sugar beet, with a total of 64 events, have been approved for import as processing material in China.