The mitochondrial gene orfH79 plays a critical role in impairing both male gametophyte development and root growth in CMS-Honglian rice

<p>Abstract</p> <p>Background</p> <p>Cytoplasmic male sterility (CMS) has often been associated with abnormal mitochondrial open reading frames. The mitochondrial gene <it>orfH79 </it>is a candidate gene for causing the CMS trait in CMS-Honglian (CMS-HL) rice. However, whether the <it>orfH79 </it>expression can actually induce CMS in rice remains unclear.</p> <p>Results</p> <p>Western blot analysis revealed that the ORFH79 protein is mainly present in mitochondria of CMS-HL rice and is absent in the fertile line. To investigate the function of ORFH79 protein in mitochondria, this gene was fused to a mitochondrial transit peptide sequence and used to transform wild type rice, where its expression induced the gametophytic male sterile phenotype. In addition, excessive accumulation of reactive oxygen species (ROS) in the microspore, a reduced ATP/ADP ratio, decreased mitochondrial membrane potential and a lower respiration rate in the transgenic plants were found to be similar to those in CMS-HL rice. Moreover, retarded growth of primary and lateral roots accompanied by abnormal accumulation of ROS in the root tip was observed in both transgenic rice and CMS-HL rice (YTA).</p> <p>Conclusion</p> <p>These results suggest that the expression of <it>orfH79 </it>in mitochondria impairs mitochondrial function, which affects the development of both male gametophytes and the roots of CMS-HL rice.</p

Comparison of wild rice (Oryza longistaminata) tissues identifies rhizome-specific bacterial and archaeal endophytic microbiomes communities and network structures.

Compared with root-associated habitats, little is known about the role of microbiota inside other rice organs, especially the rhizome of perennial wild rice, and this information may be of importance for agriculture. Oryza longistaminata is perennial wild rice with various agronomically valuable traits, including large biomass on poor soils, high nitrogen use efficiency, and resistance to insect pests and disease. Here, we compared the endophytic bacterial and archaeal communities and network structures of the rhizome to other compartments of O. longistaminata using 16S rRNA gene sequencing. Diverse microbiota and significant variation in community structure were identified among different compartments of O. longistaminata. The rhizome microbial community showed low taxonomic and phylogenetic diversity as well as the lowest network complexity among four compartments. Rhizomes exhibited less phylogenetic clustering than roots and leaves, but similar phylogenetic clustering with stems. Streptococcus, Bacillus, and Methylobacteriaceae were the major genera in the rhizome. ASVs belonging to the Enhydrobacter, YS2, and Roseburia are specifically present in the rhizome. The relative abundance of Methylobacteriaceae in the rhizome and stem was significantly higher than that in leaf and root. Noteworthy type II methanotrophs were observed across all compartments, including the dominant Methylobacteriaceae, which potentially benefits the host by facilitating CH4-dependent N2 fixation under nitrogen nutrient-poor conditions. Our data offers a robust knowledge of host and microbiome interactions across various compartments and lends guidelines to the investigation of adaptation mechanisms of O. longistaminata in nutrient-poor environments for biofertilizer development in agriculture

Overexpression of a Vesicle Trafficking Gene, OsRab7, Enhances Salt Tolerance in Rice

High soils salinity is a main factor affecting agricultural production. Studying the function of salt-tolerance-related genes is essential to enhance crop tolerance to stress. Rab7 is a small GTP-binding protein that is distributed widely among eukaryotes. Endocytic trafficking mediated by Rab7 plays an important role in animal and yeast cells, but the current understanding of Rab7 in plants is still very limited. Herein, we isolated a vesicle trafficking gene, OsRab7, from rice. Transgenic rice over-expressing OsRab7 exhibited enhanced seedling growth and increased proline content under salt-treated conditions. Moreover, an increased number of vesicles was observed in the root tip of OsRab7 transgenic rice. The OsRab7 over-expression plants showed enhanced tolerance to salt stress, suggesting that vacuolar trafficking is important for salt tolerance in plants

Comparative proteomic analysis of Methanothermobacter thermautotrophicus reveals methane formation from H2 and CO2 under different temperature conditions

Abstract The growth of all methanogens is limited to a specific temperature range. However, Methanothermobacter thermautotrophicus can be found in a variety of natural and artificial environments, the temperatures of which sometimes even exceed the temperature growth ranges of thermophiles. As a result, the extent to which methane production and survival are affected by temperature remains unclear. To investigate the mechanisms of methanogenesis that Archaea have evolved to cope with drastic temperature shifts, the responses of Methanothermobacter thermautotrophicus to temperature were investigated under a high temperature growth (71°C) and cold shock (4°C) using Isobaric tags for relative and absolute quantitation (iTRAQ). The results showed that methane formation is decreased and that protein folding and degradation are increased in both high‐ and low‐temperature treatments. In addition, proteins predicted to be involved in processing environmental information processing and in cell membrane/wall/envelope biogenesis may play key roles in affecting methane formation and enhancing the response of M. thermautotrophicus to temperature stress. Analysis of the genomic locations of the genes corresponding to these temperature‐dependent proteins predicted that 77 of the genes likely to form 32 gene clusters. Here, we assess the response of M. thermautotrophicus to different temperatures and provide a new level of understanding of methane formation and cellular putative adaptive responses

Integrated transcriptomic and metabolomic analysis provides insight into the pollen development of CMS-D1 rice

Abstract Background Cytoplasmic male sterility (CMS) has greatly improved the utilization of heterosis in crops due to the absence of functional male gametophyte. The newly developed sporophytic D1 type CMS (CMS-D1) rice exhibits unique characteristics compared to the well-known sporophytic CMS-WA line, making it a valuable resource for rice breeding. Results In this research, a novel CMS-D1 line named Xingye A (XYA) was established, characterized by small, transparent, and shriveled anthers. Histological and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assays conducted on anthers from XYA and its maintainer line XYB revealed that male sterility in XYA is a result of delayed degradation of tapetal cells and abnormal programmed cell death (PCD) of microspores. Transcriptome analysis of young panicles revealed that differentially expressed genes (DEGs) in XYA, compared to XYB, were significantly enriched in processes related to chromatin structure and nucleosomes during the microspore mother cell (MMC) stage. Conversely, processes associated with sporopollenin biosynthesis, pollen exine formation, chitinase activity, and pollen wall assembly were enriched during the meiosis stage. Metabolome analysis identified 176 specific differentially accumulated metabolites (DAMs) during the meiosis stage, enriched in pathways such as α-linoleic acid metabolism, flavone and flavonol biosynthesis, and linolenic acid metabolism. Integration of transcriptomic and metabolomic data underscored the jasmonic acid (JA) biosynthesis pathway was significant enriched in XYA during the meiosis stage compared to XYB. Furthermore, levels of JA, MeJA, OPC4, OPDA, and JA-Ile were all higher in XYA than in XYB at the meiosis stage. Conclusions These findings emphasize the involvement of the JA biosynthetic pathway in pollen development in the CMS-D1 line, providing a foundation for further exploration of the molecular mechanisms involved in CMS-D1 sterility

Relative expression levels of selected proteins measured by iTRAQ and MRM in <i>B</i>. <i>napus</i> leaves under the control, 245 mM NaCl and 25% PEG 6000 treatments for 4 h.

<p>(a) FAD-binding and BBE domain-containing protein, (b) chlorophyll <i>a-b</i> binding protein CP29.3, (c) TIC110, (d) ATPase 2, (e) thylakoid lumenal 16.5 kDa protein, (f) GPI-anchored protein, (g): carbonic anhydrase. Error bars represent SD (<i>n</i> = 3). Asterisks indicate a significant difference compared with the control (<i>p</i> < 0.05).</p

Expression patterns of salt stress-specific and drought stress-specific differentially expressed proteins in each functional category.

<p>Expression patterns of salt stress-specific and drought stress-specific differentially expressed proteins in each functional category.</p

Cross-talk and specificity of signal perception and transduction in response to salt and drought stress in <i>B</i>. <i>napus</i>.

<p>The most differentially expressed signaling-related proteins were integrated and marked in red (up-regulated) or green (down-regulated). The blue region in the middle represented the cross-talk pathway shared by both the salt and drought responses. The calcium-bind EF-hand family protein, which acted as a Ca²⁺ sensor sensing Ca²⁺ ion concentration in the cytoplasm, and ZKT protein, which may act as a molecular adaptor that was regulated by phosphorylation and modulated the ROS pathway, were overlapping signaling proteins in the salt and drought responses. Differential signal receptors, small G protein, 14-3-3 pathway members, kinases and phosphatases were identified in the salt and drought responses, indicating differences in signal perception and transduction occurred in the early stage of the salt and drought responses. Abbreviations: GPI, glycosylphosphatidylinositol (GPI)-anchored protein; PLC2, phospholipase C; RABF2a, Ras-related protein RABF2a; RABB1c, Ras-related protein RABB1c; GRF8, 14-3-3-like protein GF14 kappa; GRF2, 14-3-3-like protein GF14 omega; CDPK21, calcium-dependent protein kinase 21; TOR, serine/threonine-protein kinase TOR; CTR, serine/threonine-protein kinase CTR, STN7, serine/threonine-protein kinase STN7; BSL1, serine/threonine-protein phosphatase BSL1; ZKT, protein containing PDZ, K-box and a TPR region.</p

Characterization of salt- and drought-treated <i>B</i>. <i>napus</i> leaves.

<p>(a) Chlorophyll (Chl) <i>a</i>, Chl <i>b</i>, and total Chl concentration and Chl <i>a/b</i> ratio of stress-treated or untreated leaves. Error bars represent SD (<i>n</i> = 3). fw, fresh weight. (b) Photosynthetic rate and transpiration rate of stress-treated or untreated leaves. Error bars represent SD (<i>n</i> = 3). Pn, Photosynthetic rate; Tr, Transpiration rate. (c) F_v/F_m values of stress-treated or untreated leaves. The color bar indicates F_v/F_m values from 0 to 1. Different letters (a, b, and/or c) indicate significant differences among non-stressed, drought-stressed, and salt-stressed <i>B</i>. <i>napus</i> plants based on one-way ANOVA (p < 0.05).</p