Plant Communications最新文献

Plant diseases, caused by a wide range of pathogens, severely reduce crop yield, quality and pose a threat to global food security. Developing broad-spectrum resistance (BSR) in crops is a key strategy to control crop diseases and safeguard crop production. Cloning of disease-resistance (R) genes and understanding their underlying molecular mechanisms provides new genetic resources and strategies for crop breeding. Novel genetic engineering and genome editing tools have accelerated the study of BSR genes and engineering of BSR in crops, and this area represents the primary focus of this review. We first summarize recent advances in the understanding of the plant immune system. We then examine progress in understanding molecular mechanisms underlying BSR in crops. Finally, we highlight diverse strategies employed to achieve BSR, such as gene stacking to combine multiple R genes, multiplexed genome editing of susceptibility (S) genes and promoters of executor R genes, editing cis-regulatory elements for fine-tuning gene expression, RNA interference, saturation mutagenesis, and precise genomic insertions. Genetic studies and engineering of BSR accelerate breeding of disease-resistant cultivars and crop improvement, which will act to safeguard global food security.

The introduction of Reduced height (Rht) genes into wheat varieties results in semidwarf plant architecture with largely improved lodging resistance and harvest indices. Therefore, the exploration of new Rht gene resources to breed semidwarf wheat cultivars has been a major strategy for guaranteeing high and stable grain yields of wheat since the 1960s. In this study, we report the map-based cloning of TaERF-A1, which encodes an AP2/ERF transcription factor and acts as a positive regulator of wheat stem elongation, as a new gene for regulating plant height and spike length. The natural variant TaERF-A1^JD6, characterized by a substitution from Phe (derived from Nongda3338) to Ser (derived from Jingdong6) at position 178, significantly weakened the stability of the TaERF-A1 protein. As a result, this substitution led to partly attenuated transcriptional activation of TaERF-A1-targeted downstream genes, including TaPIF4, resulting in the restriction of stem and spike elongation. Importantly, introgression of the semidwarfing-related allele TaERF-A1^JD6 in wheat materials significantly enhanced lodging resistance, especially in dense cropping systems. Therefore, our study reveals TaERF-A1^JD6 as a new Rht gene resource for breeding semidwarf wheat varieties with increased yield stability.

Heterosis is extensively utilized in the two-line hybrid breeding system. Photo-/thermo-sensitive genic male sterile (P/TGMS) lines are key components of two-line hybrid rice. TGMS lines containing tms5 have significantly advanced two-line hybrid rice breeding. We cloned the TMS5 gene and found that TMS5 is a tRNA cyclic phosphatase that can remove 2',3'-cyclic phosphate (cP) from cP-ΔCCA-tRNAs for efficient repair to ensure maintenance of mature tRNA levels. tms5 mutation causes increased cP-ΔCCA-tRNAs and reduced mature tRNAs, leading to male sterility at the restrictive temperatures. However, the regulatory network of tms5-mediated TGMS remains to be elucidated. Here, we identified that an E3 ligase OsHel2 cooperates with TMS5 to regulate TGMS at the restrictive temperatures. Consistently, both the accumulation of 2',3'-cP-ΔCCA-tRNAs and insufficiency of mature tRNAs in tms5 mutant were largely recovered in the tms5 oshel2-1 mutant. A lesion in OsHel2 results in partial readthrough of the stalled sequences, thereby evading ribosome-associated protein quality control (RQC) surveillance. Our findings reveal a mechanism by which the OsHel2 impede readthrough of stalled mRNA sequences to regulate male fertility in TGMS rice, thus providing a paradigm for investigating how disorders in the components of the RQC pathway impair cellular functions and lead to diseases or defects in other organisms.

Diatoms, a group of prevalent marine algae, contribute significantly to global primary productivity. Their substantial biomass is linked to enhanced absorption of blue-green light underwater, facilitated by fucoxanthin chlorophyll (Chl) a/c-binding proteins (FCPs), which exhibit oligomeric diversity across diatom species. Using mild clear native PAGE analysis of solubilized thylakoid membranes, we displayed monomeric, dimeric, trimeric, tetrameric, and pentameric FCPs in diatoms. Mass spectrometry analysis revealed that each oligomeric FCP has a specific protein composition, and together they constitute a large Lhcf family of FCP antennas. In addition, we resolved the structures of the Thalassiosira pseudonana FCP (Tp-FCP) homotrimer and the Chaetoceros gracilis FCP (Cg-FCP) pentamer by cryoelectron microscopy at 2.73-Å and 2.65-Å resolution, respectively. The distinct pigment compositions and organizations of various oligomeric FCPs affect their blue-green light-harvesting, excitation energy transfer pathways. Compared with dimeric and trimeric FCPs, the Cg-FCP tetramer and Cg-FCP pentamer exhibit stronger absorption by Chl c, redshifted and broader Chl a fluorescence emission, and more robust circular dichroism signals originating from Chl a-carotenoid dimers. These spectroscopic characteristics indicate that Chl a molecules in the Cg-FCP tetramer and Cg-FCP pentamer are more heterogeneous than in both dimers and the Tp-FCP trimer. The structural and spectroscopic insights provided by this study contribute to a better understanding of the mechanisms that empower diatoms to adapt to fluctuating light environments.

Two principal growth regulators, cytokinins and ethylene, are known to interact in the regulation of plant growth. However, information about the underlying molecular mechanism and positional specificity of cytokinin/ethylene crosstalk in the control of root growth is scarce. We have identified the spatial specificity of cytokinin-regulated root elongation and root apical meristem (RAM) size, both of which we demonstrate to be dependent on ethylene biosynthesis. Upregulation of the cytokinin biosynthetic gene ISOPENTENYLTRANSFERASE (IPT) in proximal and peripheral tissues leads to both root and RAM shortening. By contrast, IPT activation in distal and inner tissues reduces RAM size while leaving the root length comparable to that of mock-treated controls. We show that cytokinins regulate two steps specific to ethylene biosynthesis: production of the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC) by ACC SYNTHASEs (ACSs) and its conversion to ethylene by ACC OXIDASEs (ACOs). We describe cytokinin- and ethylene-specific regulation controlling the activity of ACSs and ACOs that are spatially discrete along both proximo/distal and radial root axes. Using direct ethylene measurements, we identify ACO2, ACO3, and ACO4 as being responsible for ethylene biosynthesis and ethylene-regulated root and RAM shortening in cytokinin-treated Arabidopsis. Direct interaction between ARABIDOPSIS RESPONSE REGULATOR 2 (ARR2), a member of the multistep phosphorelay cascade, and the C-terminal portion of ETHYLENE INSENSITIVE 2 (EIN2-C), a key regulator of canonical ethylene signaling, is involved in the cytokinin-induced, ethylene-mediated control of ACO4. We propose tight cooperation between cytokinin and ethylene signaling in the spatially specific regulation of ethylene biosynthesis as a key aspect of the hormonal control of root growth.

Sustainable alternative farming systems are gaining popularity worldwide because of the negative effects of conventional agriculture on global climate change and the environmental degradation caused by intensive use of synthetic inputs. The green farming system in China is an integrated production strategy that focuses on reducing chemical fertilizer use while increasing organic manure inputs. Despite their rapid growth as more sustainable systems over the past decades, green farming systems have not been systematically evaluated to date. We used apple production as a representative case to assess the sustainability of green farming systems. Across major apple-producing regions in China, green farming reduced the application of chemical fertilizer nitrogen (N) by 46.8% (from 412 to 219 kg ha^-1) and increased that of manure N by 33.1% (from 171 to 227 kg ha^-1) on average compared with conventional systems enhancing N use efficiency by 7.27-20.27% and reducing N losses by 8.92%-11.56%. It also slightly lowered yield by 4.34%-13.8% in four provinces. Soil fertility was improved in green orchards through increases in soil organic matter, total N, and available major nutrients. Our cradle-to-farm-gate life-cycle assessment revealed that green farming helped to mitigate greenhouse gas emissions by an average of 12.6%, potentially contributing to a reduction of 165 239 t CO₂ eq annually in major apple-producing areas. In addition, green farming achieved 39.3% higher profitability ($7180 ha^-1 year^-1) at the farmer level. Our study demonstrates the potential of green production of apples for the development of sustainable agriculture in China. These findings advance our understanding of sustainable alternative farming systems and offer perspectives for the sustainable development of global agriculture.

The transcriptome serves as a bridge that links genomic variation to phenotypic diversity. A vast number of studies using next-generation RNA sequencing (RNA-seq) over the last 2 decades have emphasized the essential roles of the plant transcriptome in response to developmental and environmental conditions, providing numerous insights into the dynamic changes, evolutionary traces, and elaborate regulation of the plant transcriptome. With substantial improvement in accuracy and throughput, direct RNA sequencing (DRS) has emerged as a new and powerful sequencing platform for precise detection of native and full-length transcripts, overcoming many limitations such as read length and PCR bias that are inherent to short-read RNA-seq. Here, we review recent advances in dissecting the complexity and diversity of plant transcriptomes using DRS as the main technological approach, covering many aspects of RNA metabolism, including novel isoforms, poly(A) tails, and RNA modification, and we propose a comprehensive workflow for processing of plant DRS data. Many challenges to the application of DRS in plants, such as the need for machine learning tools tailored to plant transcriptomes, remain to be overcome, and together we outline future biological questions that can be addressed by DRS, such as allele-specific RNA modification. This technology provides convenient support on which the connection of distinct RNA features is tightly built, sustainably refining our understanding of the biological functions of the plant transcriptome.