Quercus longispica is a dominant shrub in the Himalayan subalpine region, demonstrating high levels of persistence despite high seed predation and extreme climatic conditions. However, its seed germination ecology and adaptations for seedling recruitment remain poorly understood. This study investigated the effects of temperature, water potential, and insect damage on seed germination and seedling establishment. Pre-germination seed traits and seed-to-seedling ontogeny were systematically analyzed. Our results demonstrated that seed germination percentages decreased with increasing insect damage across all temperature and water potential treatments. Cool temperatures (5-10 degrees C) yielded the highest germination percentages, potentially due to the suppression of parasitoid activity and mildew growth. While drought conditions also suppressed parasitoid activity, they significantly increased seed mortality. Despite a decline in seedling performance with increasing seed damage, overall seedling establishment remained robust. Several adaptive traits enable Q. longispica to persist in its harsh environment. Multi-seeded, non-apical embryos combined with rapid germination help embryos evade or escape damage from parasitism and predation. The rapid elongation of cotyledonary petioles pushes the embryo axis into the soil, with rapid nutrient and water transfer from the cotyledon to the taproot, thereby avoiding the threats of predation, drought, cold, and wildfire. Additionally, temperature-regulated epicotyl dormancy at the post-germination stage prevents the emergence of cold-intolerant seedlings in winter. This study provides the first comprehensive description of seed-to-seedling ontogeny in this Himalayan subalpine oak, offering crucial insights into the adaptive mechanisms that facilitate successful seedling recruitment in the challenging subalpine habitats.

Yam is an important medicinal and edible dual-purpose plant with high economic value. However, nematode damage severely affects its yield and quality. One of the major effects of nematode infestations is the secondary infection of pathogenic bacteria or fungi through entry wounds made by the nematodes. Understanding the response of the symbiotic microbial community of yam plants to nematodes is crucial for controlling such a disease. In this study, we investigated the rhizosphere and how endophytic microbiomes shift after nematode infection during the tuber expansion stage in the Dioscorea opposita Thunb. cultivar Tiegun. Our results revealed that soil depth affected the abundance of nematodes, and the relative number of Meloidogyne incognita was higher in the diseased soil at a depth of 16 to 40 cm than those at a depth of 0 to 15 and 41 to 70 cm. The abundance of and interactions among soil microbiota members were significantly correlated with root-knot nematode (RKN) parasitism at various soil depths. However, the comparison of the microbial alpha-diversity and composition between healthy and diseased rhizosphere soil showed no difference. Compared with healthy soils, the co-occurrence networks of M. incognita-infested soils included a higher ratio of positive correlations linked to plant health. In addition, we detected a higher abundance of certain taxonomic groups belonging to Chitinophagaceae and Xanthobacteraceae in the rhizosphere of RKN-infested plants. The nematodes, besides causing direct damage to plants, also possess the ability to act synergistically with other pathogens, especially Ramicandelaber and Fusarium, leading to the development of disease complexes. In contrast to soil samples, RKN parasitism specifically had a significant effect on the composition and assembly of the root endophytic microbiota. The RKN colonization impacted a wide variety of endophytic microbiomes, including Pseudomonas, Sphingomonas, Rhizobium, Neocosmospora, and Fusarium. This study revealed the relationship between RKN disease and changes in the rhizosphere and endophytic microbial community, which may provide novel insights that help improve biological management of yam RKNs.

Under natural conditions, crops typically suffer from severe challenges due to the increasing of abiotic and biotic stresses which severely affect plant growth and reduc crop yield. The present study investigated the single and combined impacts of Sclerotinia sclerotiorum and salinity stress on common bean (Phaseolus vulgaris L.) seedling which is scarcely studied. The study evaluated the in vitro and in vivo influence of two salinity tolerant Trichoderma isolates, T. koningii and T. harzianum against S. sclerotiorum under salinity stress. The results showed the ability of T. koningii and T. harzianum to grow and sporulate at high levels of salinity, 80 mM NaCl, without significantly impacting their ability to produce cell wall degrading enzymes, cellulase and chitinase. Amylase and proteinase (Prb1) genes were detected in T. harzianum. The in vitro assay revealed that both isolates could inhibit the growth of S. sclerotiorum under high salinity concentrations. In a greenhouse experiment, both Trichoderma isolates ameliorated the damaging impacts of S. sclerotiorum under salinity stress on common bean seedlings' germination and growth characteristics compared to their untreated control. Both bioagents significantly attenuated the damping-off and collar/stem rot percentages of infected common bean under salinity stress. Salinity stress intensified the effect of S. sclerotiorum on photosynthetic pigments, induced oxidative and nitrative stress, hampered ionic homeostasis, and deactivated antioxidants and defense-related molecules. On the other hand, Trichoderma isolates restrained the reduction of chlorophylls and carotenoids, ascorbate, reduced glutathione, flavonoids, phenolics, and various antioxidant enzymes, especially for single stresses and T. harzianum. All these upregulations reflected in keeping the cell membranes of common beans seedling more stable where the levels of lipid peroxidation and methylglyoxal due to the reduction of reactive oxygen species and upregulation of nitric oxide, which expressed better growth under pathogen attack or/and saline. The tested isolates, T. koningii and T. harzianum could be used as effective biological control against S. sclerotiorum on common beans in saline soils or areas irrigated with saline water.