Casuarina glauca grows in coastal areas suffering long-term damage due to high salt stress. Arbuscular mycorrhizal fungi (AMF) can colonize their roots to alleviate the effects of salt stress. However, the specific molecular mechanism still needs to be further explored. Our physiological and biochemical analysis showed that Rhizophagus irregularis inoculation played an important role in promoting plant growth, regulating ion balance, and changing the activity of antioxidant enzymes. Transcriptome analysis of roots revealed that 1827 differentially expressed genes (DEGs) were affected by both R. irregularis inoculation and NaCl stress. The enrichment of GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) showed that most of these DEGs were significantly enriched in ion transport, antioxidant enzyme activity, carbohydrate metabolism, and cell wall. HAK5, KAT3, SKOR, PIP1-2, PER64, CPER, GLP10, MYB46, NAC43, WRKY1, and WRKY19 were speculated to play the important roles in the salt tolerance of C. glauca induced by R. irregularis. Our research systematically revealed the effect of R. irregularis on the gene expression of C. glauca roots under salt stress, laying a theoretical foundation for the future use of AMF to enhance plant tolerance to salt stress.
Arbuscular mycorrhizal fungi (AMF) promote plants to absorb more water and nutrients and improve their stress resistance. As the main signal transducer, the mitogen‐activated protein kinase (MAPK) cascade plays a vital role in drought stress. However, how the MAPK family genes of mycorrhizal plants respond to stress is still not clear. Our study analyzed physiological indexes and expression profiles of MAPK family genes of Populus simonii × P. nigra under two inoculation treatments (inoculated with or without Rhizophagus irregularis) and two water conditions (well‐watered or drought stress). The results showed that the stronger photosynthesis of mycorrhizal plants may be mediated by MAPK genes induced by AMF. Mycorrhizal plants showed lower oxidative damage and drought sensitivity. Mycorrhiza downregulated the expression of PsnMAPK7‐2, PsnMAPK16‐1, PsnMAPK19‐2, and PsnMAPK20‐2 which negatively regulate drought tolerance and induced specific PsnMAPKs in roots which activate transcription factors to regulate downstream gene expressions, enhancing drought tolerance. This is the first time to identify part of the MAPK gene family of P. simonii × P. nigra at the genome level and study MAPK genes in mycorrhizal forest trees. This is helpful to understand the function of the MAPK gene family in response to drought of mycorrhizal plants and lays a foundation for afforestation by using mycorrhizal saplings.
IntroductionSaline-alkali stress seriously endangers the normal growth of Populus simonii×P. nigra. Arbuscular mycorrhizal (AM) fungi can enhance the saline-alkali tolerance of plants by establishing a symbiotic relationship with them.MethodsIn this study, a pot experiment was conducted to simulate a saline-alkali environment where Populus simonii×P. nigra were inoculated with Funneliformis mosseae to explore their effects on the saline-alkali tolerance of Populus simonii×P. nigra.Results and DiscussionOur results show that a total of 8 NHX gene family members are identified in Populus simonii×P. nigra. F. mosseae regulate the distribution of Na+ by inducing the expression of PxNHXs. The pH value of poplar rhizosphere soil is reduced, result in the promote absorption of Na+ by poplar, that ultimately improved the soil environment. Under saline-alkali stress, F. mosseae improve the chlorophyll fluorescence and photosynthetic parameters of poplar, promote the absorption of water, K+ and Ca2+, thus increase the plant height and fresh weight of aboveground parts, and promote the growth of poplar. Our results provide a theoretical basis for further exploring the application of AM fungi to improve the saline-alkali tolerance of plants.
Aims: Biocontrol is an emerging trend aimed at reducing chemical input while increasing plant fitness, productivity and resistance to diseases in sustainable agriculture. An antagonist, pY11T‐3‐1, was herein characterized for potential applications against soil‐borne plant diseases.
Methods and Results: In vitro antagonistic assays, the antagonist pY11T‐3‐1 was demonstrated able to obviously reduce the occurrence of the soft rot disease on Pinellia ternata, potato, pepper, tomato, cucumber and eggplant tubers or fruits, with higher prevention (90%) on P. ternata. It showed a broad antagonistic spectrum against 23 tested bacterial and fungal phytopathogens, which were distributed in 14 genus and 17 species. However, it inhibited only two of the seven bacterial nonpathogens. Phenotypic characterizations showed that the antagonist pY11T‐3‐1 was similar to Pseudomonas aeruginosa. Its major fatty acids were 18:1 w7c (22·17%), 16:0 (20·21%), 12:0 2OH (12·45%), 16:1w7c/15 iso2OH (10·95%) and 10:0 3OH (10·79%), which is a different profile from that of Ps. aeruginosa. The 16S rRNA and gyr B gene sequences shared 100 and 99% similarity with Ps. aeruginosa, respectively. The phylogenetic trees showed that it was clustered with Ps. aeruginosa.
Conclusions: The antagonist pY11T‐3‐1 was characterized as Ps. aeruginosa with a unique fatty acid profile.
Significance and Impact of the Study: With broad antagonistic spectrum and host selectivity, the antagonist pY11T‐3‐1 may provide a more environmental and economical alternative to the control of soil‐borne disease on P. ternata, which needs further investigation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.