Litchi has great economic significance as a global fruit crop.  However, the advancement of litchi functional genomics has encountered substantial obstacles due to its recalcitrance to stable transformation.  Here, we present an efficacious Agrobacterium tumefaciens-mediated transformation system in somatic embryos of ‘Heiye’ litchi.  This system was developed through the optimization of key variables encompassing explant selection, A. tumefaciens strain delineation, bacterium concentration, infection duration, and infection methodology.  The subsequent validation of the transformation technique in litchi was realized through the ectopic expression of LcMYB1, resulting in the generation of transgenic calli.  However, the differentiation of transgenic calli into somatic embryos encountered substantial challenges.  To delineate the intricate molecular underpinnings of LcMYB1’s inhibitory role in somatic embryo induction, a comprehensive transcriptome analysis was conducted that encompassed embryogenic calli (C), globular embryos (G), and transgenic calli (TC).  A total of 1,166 common differentially expressed genes (DEGs) were identified between C-vs.-G and C-vs.-TC.  Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that these common DEGs were mostly related to plant hormone signal transduction pathways.  Furthermore, RT-qPCR corroborated the pronounced down-regulation of numerous genes that are associated with somatic embryo induction within the transgenic calli.  The development of this transformation system provides valuable support for functional genomics research in litchi.

Land use influences soil biota community composition and diversity, and then belowground ecosystem processes and functions.  To characterize the effect of land use on soil biota, soil nematode communities in crop land, forest land and fallow land were investigated in six regions of northern China.  Generic richness, diversity, abundance and biomass of soil nematodes was the lowest in crop land.  The richness and diversity of soil nematodes were 28.8 and 15.1% higher in fallow land than in crop land, respectively.  No significant differences in soil nematode indices were found between forest land and fallow land, but their network keystone genera composition was different.  Among the keystone genera, 50% of forest land genera were omnivores-predators and 36% of fallow land genera were bacterivores.  The proportion of fungivores in forest land was 20.8% lower than in fallow land.  The network complexity and the stability were lower in crop land than forest land and fallow land.  Soil pH, NH₄⁺-N and NO₃^–-N were the major factors influencing the soil nematode community in crop land while soil organic carbon and moisture were the major factors in forest land.  Soil nematode communities in crop land influenced by artificial management practices were more dependent on the soil environment than communities in forest land and fallow land.  Land use induced soil environment variation and altered network relationships by influencing trophic group proportions among keystone nematode genera.  

Hyphal fusion (anastomosis) is a common process serving many important functions at various developmental stages in the life cycle of ascomycetous fungi.  However, the biological roles and molecular mechanisms in plant pathogenic fungi were widely unknown.  In this study, a hyphal fusion protein FpHam-2 was screened from a T-DNA insertion mutant library of Fusarium pseudograminearum, and FpHam-2 interacts with another 2 hyphal fusion protein homologues FpHam-3 and FpHam-4.  Each of these 3 genes deletion mutant revealed in similar defective phenotypes compared with the WT and complemented strains, including reduction in growth rate, defects in hyphal fusion and conidiation, more sensitive for cell membrane, cell wall and oxidative stress responses, and decreased in virulence.  The yeast two-hybrid assay was used to identify that FpHam-2 interacts with 3 autophagy-related proteins, including FpAtg3, FpAtg28 and FpAtg33.  Furthermore, FpHam-2-deletion mutant showed decreased accumulation of autophagic bodies in hypha.  In conclusion, FpHam-2, FpHam-3 and FpHam-4 have an essential role for hyphal fusion and regulating the growth, conidiation and virulence in F. pseudograminearum.