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Garden asparagus ( Asparagus officinalis L.) is a kind of nutritious and healthy vegetable with important economic value in the world. China has become the largest production country of garden asparagus in the world. But the seeds mainly depend on import, so we need to innovate breeding system and improve the international competitiveness of domestic asparagus varieties. Genetic analysis demonstrated that the genetic variation of garden asparagus was low and its heterosis was weak among cultivars. Inter-specific hybridization is an important means to utilize heterosis, but the relationship between the classical taxonomy and molecular phylogeny of the genus Asparagus is disordered, which limits the development of interspecific hybridization breeding. In this genus, thirty-one species have been found in China, which is an effective genetic resource for the utilization of heterosis among Asparagus species. In order to provide reference for the next step to clarify the phylogenetic relationship of this genus and to carry out the interspecific hybrid breeding of garden asparagus in the near future, the research progress of its classical and molecular phylogeny of this genus is reviewed in this study.

The garden asparagus stem blight caused by filamentous fungus Phomopsis asparagi exposes a serious threat on asparagus production globally. However, to present, we understand poorly about the molecular mechanisms of fungal pathogenicity. To facilitate functional genomics research of P. asparagi, here we developed a highly efficient and stable Agrobacterium tumefaciens-mediated transformation approach which yielded 150–200 transformants per 1 × 106 conidia. Our results indicated that 25 °C, acetosyringone concentration of 150 μmol/L, and 72 h were recommended as optimal co-cultivation conditions for the transformation. Using this transformation approach, we constructed a T-DNA insertion mutant library containing 1253 strains. Twenty randomly selected T-DNA insertion mutants were able to grow on 0.2 × PDA selective media after five successive subcultures without selective pressure, indicating that the exogenous T-DNA was stably integrated into the P. asparagi genome. We confirmed several randomly selected mutants using PCR with primers specific to the hph gene. Southern blots suggested that three out of the five selected mutants have a single T-DNA insertion. Interestingly, multiple mutant candidates with growth defects were obtained from the growth assay. Moreover, several mutants were selected for further analysis on the T-DNA flanking sequences through TAIL-PCR analysis. A sequence comparison of total junction fragments implied that the insertion of T-DNA within P. asparagi genome appeared to be a random event. The transformation technology and genetic resources developed here will facilitate studies of pathogenic mechanisms in this devastating filamentous fungal pathogen of garden asparagus.

Sex chromosomes evolved from autosomes many times across the eukaryote phylogeny. Several models have been proposed to explain this transition, some involving male and female sterility mutations linked in a region of suppressed recombination between X and Y (or Z/W, U/V) chromosomes. Comparative and experimental analysis of a reference genome assembly for a double haploid YY male garden asparagus (Asparagus officinalis L.) individual implicates separate but linked genes as responsible for sex determination. Dioecy has evolved recently within Asparagus and sex chromosomes are cytogenetically identical with the Y, harboring a megabase segment that is missing from the X. We show that deletion of this entire region results in a male-to-female conversion, whereas loss of a single suppressor of female development drives male-to-hermaphrodite conversion. A single copy anther-specific gene with a male sterile Arabidopsis knockout phenotype is also in the Y-specific region, supporting a two-gene model for sex chromosome evolution.

This study evaluated that grafting as an effective measure on resistance disease in continuous cropping system has a remarkable impact on improving the microbial community population and structure conditions in the rhizosphere of eggplant, which lead to a highly suppressive on the disease incidence. Verticillium dahliae, microbial community and soil enzyme activities in the rhizosphere of both grafted and self-rooted eggplants investigations were conducted in different eggplant growth stages in pot trials to determine the effects of grafting on the soil microbiological properties. In addition, an assessment of the bio-control effects of antagonistic microbes isolated from rhizosphere of grafted eggplants on the incidence of Verticillium wilt was performed. Grafted eggplants exhibited strong resistance (nearly 90%) with a lower pathological incident index. Amounts of Verticillium dahliae in the rhizosphere of grafted eggplants were lower before the fruiting stage compared to non-grafted self-rooting eggplants. Although each general classification of microbes (bacteria, actinomyces and fungi) was reduced over all growth stages by grafting, the ranges of bacterial and actinomycete reduction in the rhizosphere of grafted eggplants were lower compared to self-rooted eggplants. Experimental evidence indicated that grafting increased the relative ratios of Bacteria to Fungi and Actinomycete to Fungi. In terms of functional microbes, amounts of azotobacteria, ammonifying and nitrifying bacteria were significantly higher in grafted eggplants than self-rooted eggplants, especially after floral initiation. Compared to Control, grafting leaded to a significantly positive impacts on invertase, protein enzyme, urease, peroxidase and catalase activities in the rhizosphere of eggplants. Using antagonistic strains have showed strong suppression of Verticillium dahliae growth to study the prevention and curative effects on Verticillium wilt in pot trials.