OsOLP1 contributes to drought tolerance in rice by regulating ABA biosynthesis and lignin accumulation

Rice, as a major staple crop, employs multiple strategies to enhance drought tolerance and subsequently increase yield. Osmotin-like proteins have been shown to promote plant resistance to biotic and abiotic stress. However, the drought resistance mechanism of osmotin-like proteins in rice remains unclear. This study identified a novel osmotin-like protein, OsOLP1, that conforms to the structure and characteristics of the osmotin family and is induced by drought and NaCl stress. CRISPR/Cas9-mediated gene editing and overexpression lines were used to investigate the impact of OsOLP1 on drought tolerance in rice. Compared to wild-type plants, transgenic rice plants overexpressing OsOLP1 showed high drought tolerance with leaf water content of up to 65%, and a survival rate of 53.1% by regulating 96% stomatal closure and more than 2.5-fold proline content promotion through the accumulation of 1.5-fold endogenous ABA, and enhancing about 50% lignin synthesis. However, OsOLP1 knockout lines showed severely reduced ABA content, decreased lignin deposition, and weakened drought tolerance. In conclusion, the finding confirmed that OsOLP1 drought-stress modulation relies on ABA accumulation, stomatal regulation, proline, and lignin accumulation. These results provide new insights into our perspective on rice drought tolerance

FSFP: Transfer Learning From Long Texts to the Short

Abstract: Transfer learning is a method that studies how to identify the useful knowledge and skills in the previous tasks, and uses them to the new tasks or domains. At present, the research on transfer learning mostly focuses on the field of long texts. However, the source data should be given for the transportation from long texts to the short ones, and the priori probability distribution of the data should be given at the same time. In order to solve the problems, the algorithm which is called FSFP (Free Source selection Free Priori probability distribution) is proposed. It can transfer knowledge from the long texts to the short ones. Latent semantic analysis is used to extract the key words as seed characteristic sets, which are semantically related to the long texts from the target domain. And then the graph structure of online information is built. With the help of the improved Laplacian Eigenmaps, the feature representations of highdimensional data are mapped to a low-dimensional space. Lastly, the target data are classified in the constraint of minimizing the mutual information between the instance and the feature representation. The experimental results on large data sets show the effectiveness of the new algorithm

Involvement of hrpX and hrpG in the Virulence of Acidovorax citrulli Strain Aac5, Causal Agent of Bacterial Fruit Blotch in Cucurbits

Acidovorax citrulli causes bacterial fruit blotch, a disease that poses a global threat to watermelon and melon production. Despite its economic importance, relatively little is known about the molecular mechanisms of pathogenicity and virulence of A. citrulli. Like other plant-pathogenic bacteria, A. citrulli relies on a type III secretion system (T3SS) for pathogenicity. On the basis of sequence and operon arrangement analyses, A. citrulli was found to have a class II hrp gene cluster similar to those of Xanthomonas and Ralstonia spp. In the class II hrp cluster, hrpG and hrpX play key roles in the regulation of T3SS effectors. However, little is known about the regulation of the T3SS in A. citrulli. This study aimed to investigate the roles of hrpG and hrpX in A. citrulli pathogenicity. We found that hrpG or hrpX deletion mutants of the A. citrulli group II strain Aac5 had reduced pathogenicity on watermelon seedlings, failed to induce a hypersensitive response in tobacco, and elicited higher levels of reactive oxygen species in Nicotiana benthamiana than the wild-type strain. Additionally, we demonstrated that HrpG activates HrpX in A. citrulli. Moreover, transcription and translation of the type 3-secreted effector (T3E) gene Aac5_2166 were suppressed in hrpG and hrpX mutants. Notably, hrpG and hrpX appeared to modulate biofilm formation. These results suggest that hrpG and hrpX are essential for pathogenicity, regulation of T3Es, and biofilm formation in A. citrulli

FSFP: Transfer Learning From Long Texts to the Short

Transfer learning is a method that studies how to identify the useful knowledge and skills in the previous tasks, and uses them to the new tasks or domains. At present, the research on transfer learning mostly focuses on the field of long texts. However, the source data should be given for the transportation from long texts to the short ones, and the priori probability distribution of the data should be given at the same time. In order to solve the problems, the algorithm which is called FSFP (Free Source selection Free Priori probability distribution) is proposed. It can transfer knowledge from the long texts to the short ones. Latent semantic analysis is used to extract the key words as seed characteristic sets, which are semantically related to the long texts from the target domain. And then the graph structure of online information is built. With the help of the improved Laplacian Eigenmaps, the feature representations of highdimensional data are mapped to a low-dimensional space. Lastly, the target data are classified in the constraint of minimizing the mutual information between the instance and the feature representation. The experimental results on large data sets show the effectiveness of the new algorithm

Research on forming method of additive manufacturing of frozen sand mold

In order to promote the green and sustainable development of the foundry industry, it is necessary to further explore new methods and technologies for green foundry. This paper innovatively proposes a method of additive manufacturing of frozen sand mold, using water as the binder instead of resin binders for additive manufacturing in low-temperature environments, which effectively solves the problems of harmful gas emissions during the pouring process and the difficulty of direct recycling of molding sand, and realizes high-performance green casting of complex castings. In this paper, the liquid-solid phase transition mechanism of the binder for additive manufacturing of frozen sand mold and the change law of the normal temperature field and phase transition field of the pre-cooled powder bed porous medium at different temperatures are studied, and the process window of additive manufacturing of frozen sand mold is obtained, which provides a new green casting method for the foundry field

Lignin and Its Pathway-Associated Phytoalexins Modulate Plant Defense against Fungi

Fungi infections cause approximately 60–70% yield loss through diseases such as rice blast, powdery mildew, Fusarium rot, downy mildew, etc. Plants naturally respond to these infections by eliciting an array of protective metabolites to confer physical or chemical protection. Among plant metabolites, lignin, a phenolic compound, thickens the middle lamella and the secondary cell walls of plants to curtail fungi infection. The biosynthesis of monolignols (lignin monomers) is regulated by genes whose transcript abundance significantly improves plant defense against fungi. The catalytic activities of lignin biosynthetic enzymes also contribute to the accumulation of other defense compounds. Recent advances focus on modifying the lignin pathway to enhance plant growth and defense against pathogens. This review presents an overview of monolignol regulatory genes and their contributions to fungi immunity, as reported over the last five years. This review expands the frontiers in lignin pathway engineering to enhance plant defense

Genome-wide identification, phylogenomics, and expression analysis of benzoxazinoids gene family in rice (Oryza sativa)

Benzoxazinoids (BXs) are potent secondary metabolites that affect plants' biotic and abiotic interactions. Extensive studies on the functions of benzoxazinoids in mediating biotic and abiotic stressors have been reported in maize, wheat, and rye. However, little is known about BXs biosynthesis in rice. This study presents a genome-wide analysis of forty-three Oryzae sativa BXs genes that form diphyletic clusters in a neighbor-joining tree. The first cluster comprised genes that encode the first four steps in BXs biosynthesis (BX2–BX4), leading to the production of 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA). The second cluster mainly comprised BX6 and BX7 genes responsible for BXs glycosylation. Furthermore, BX proteins harboring similar conserved motifs were found to group according to their phylogenetic clustering. Whereas the P450 superfamily protein is conserved in BX1-BX4 proteins, the UDP-glucosyltransferase is conserved in BX7 members. These proteins were found to be strategically localized in subcellular compartments where their catalytic activities are executed. BX1 proteins are localized in the chloroplasts, where they encode the production of indole. BX6 were identified as cytoplasmic proteins, where they are involved in the hydroxylation of DIBOA-Glycoside to 2-(2,4,7-trihydroxy-8-methoxy-1,4-benzoxazine-3-one)-β-d-glucopyranose (TRIBOA-Glycoside). Further investigation of the molecular addresses showed that BX proteins tend to localize together on chromosomes based on their functions. Moreover, the expression profiles of these proteins vary at various developmental stages in rice tissues and organs, highlighting the potential for biotic and abiotic interactions. The prospects of BXs genes in growth induction were also investigated by analyzing their responsiveness to plant hormones and nutrient treatment. BX gene expression is affected by exogenous treatment with auxin and gibberellin as well as nitrogen, potassium, and phosphorus contents, suggesting a possible role in growth mediation. This study lays the foundation for further studies to elucidate the functions of BX genes in rice

Hcp of the Type VI Secretion System (T6SS) in <i>Acidovorax citrulli</i> Group II Strain Aac5 Has a Dual Role as a Core Structural Protein and an Effector Protein in Colonization, Growth Ability, Competition, Biofilm Formation, and Ferric Iron Absorption

A type VI secretion system (T6SS) gene cluster has been reported in Acidovorax citrulli. Research on the activation conditions, functions, and the interactions between key elements in A. citrulli T6SS is lacking. Hcp (Hemolysin co-regulated protein) is both a structural protein and a secretion protein of T6SS, which makes it a special element. The aims of this study were to determine the role of Hcp and its activated conditions to reveal the functions of T6SS. In virulence and colonization assays of hcp deletion mutant strain Δhcp, tssm (type VI secretion system membrane subunit) deletion mutant strain Δtssm and double mutant ΔhcpΔtssm, population growth was affected but not virulence after injection of cotyledons and seed-to-seedling transmission on watermelon. The population growth of Δhcp and Δtssm were lower than A. citrulli wild type strain Aac5 of A. citrulli group II at early stage but higher at a later stage. Deletion of hcp also affected growth ability in different culture media, and the decline stage of Δhcp was delayed in KB medium. Biofilm formation ability of Δhcp, Δtssm and ΔhcpΔtssm was lower than Aac5 with competition by prey bacteria but higher in KB and M9-Fe3+ medium. Deletion of hcp reduced the competition and survival ability of Aac5. Based on the results of Western blotting and qRT-PCR analyses, Hcp is activated by cell density, competition, ferric irons, and the host plant. The expression levels of genes related to bacterial secretion systems, protein export, and several other pathways, were significantly changed in the Δhcp mutant compared to Aac5 when T6SS was activated at high cell density. Based on transcriptome data, we found that a few candidate effectors need further identification. The phenotypes, activated conditions and transcriptome data all supported the conclusion that although there is only one T6SS gene cluster present in the A. citrulli group II strain Aac5, it related to multiple biological processes, including colonization, growth ability, competition and biofilm formation

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<p>Acidovorax citrulli causes bacterial fruit blotch, a disease that poses a global threat to watermelon and melon production. Despite its economic importance, relatively little is known about the molecular mechanisms of pathogenicity and virulence of A. citrulli. Like other plant-pathogenic bacteria, A. citrulli relies on a type III secretion system (T3SS) for pathogenicity. On the basis of sequence and operon arrangement analyses, A. citrulli was found to have a class II hrp gene cluster similar to those of Xanthomonas and Ralstonia spp. In the class II hrp cluster, hrpG and hrpX play key roles in the regulation of T3SS effectors. However, little is known about the regulation of the T3SS in A. citrulli. This study aimed to investigate the roles of hrpG and hrpX in A. citrulli pathogenicity. We found that hrpG or hrpX deletion mutants of the A. citrulli group II strain Aac5 had reduced pathogenicity on watermelon seedlings, failed to induce a hypersensitive response in tobacco, and elicited higher levels of reactive oxygen species in Nicotiana benthamiana than the wild-type strain. Additionally, we demonstrated that HrpG activates HrpX in A. citrulli. Moreover, transcription and translation of the type 3-secreted effector (T3E) gene Aac5_2166 were suppressed in hrpG and hrpX mutants. Notably, hrpG and hrpX appeared to modulate biofilm formation. These results suggest that hrpG and hrpX are essential for pathogenicity, regulation of T3Es, and biofilm formation in A. citrulli.</p