Optimization and standardization of transient expression assays for gene functional analyses in strawberry fruits

Strawberry is increasingly used as a model plant for research on fruit growth and development.The transient gene manipulation(TGM)technique is widely used to determine the function of plant genes,including those in strawberry fruits.However,its reliable application for the precise identification of gene function has been difficult owing to the lack of conditional optimization.In this study,we found that successful transient gene manipulation requires optimization,with the vector type,temperature,and fruit developmental stage being three major factors determining success.Notably,we found that transient gene manipulation was feasible only from the large green fruit stage onwards,making it especially suitable for identifying genes involved in strawberry fruit ripening.Furthermore,we established a method called percentage difference of phenotype(PDP),in which the functional effect of a gene could be precisely and efficiently identified in strawberry fruits.This method can be used to estimate the functional effect of a gene as a value from 0 to 100%,such that different genes can be quantitatively compared for their relative abilities to regulate fruit ripening.This study provides a useful tool for accelerating research on the molecular basis of strawberry fruit ripening.

A review of research progress on continuous cropping obstacles

Due to the increasing global population and limited land resources, continuous cropping has become common. However, after a few years of continuous cropping, obstacles often arise that cause soil degeneration, decreased crop yield and quality, and increased disease incidence, resulting in significant economic losses. It is essential to understand the causes and mitigation mechanisms of continuous cropping obstacles(CCOs) and then develop appropriate methods to overcome them. This review systematically summarizes the causes and mitigation measures of soil degradation in continuous cropping through a meta-analysis. It was concluded that not all continuous cropping systems are prone to CCOs. Therefore, it is necessary to grasp the principles governing the occurrence of diseases caused by soilborne pathogens in different cropping systems, consider plant–soil-organisms interactions as a system, scientifically regulate the physical and chemical properties of soils from a systems perspective, and then regulate the structure of microbial food webs in the soil to achieve a reduction in diseases caused by soilborne pathogens and increase crop yield ultimately. This review provides reference data and guidance for addressing this fundamental problem.

A review of soil nematodes as biological indicators for the assessment of soil health

Healthy soils are essential for sustainableagricultural development and soil health requires carefulassessment with increasing societal concern over envir-onmentally friendly agricultural development. Soil healthis the capacity of soil to function within ecologicalboundaries to sustain productivity, maintain environmentalquality, and promote plant and animal health. Physical,chemical and biological indicators are used to evaluate soilhealth;the biological indicators include microbes, proto-zoa and metazoa. Nematodes are the most abundantmetazoa and they vary in their sensitivity to pollutants andenvironmental disturbance. Soil nematode communitiesare useful biological indicators of soil health, withcommunity characteristics such as abundance, diversity,community structure and metabolic footprint all closelycorrelated with the soil environment. The community size,complexity and structure reflect the condition of the soil.Both free-living and plant parasitic nematodes are effec-tive ecological indicators, contributing to nutrient cyclingand having important roles as primary, secondary andtertiary consumers in food webs. Tillage inversion,cropping patterns and nutrient management may havestrong effects on soil nematodes, with changes in soilnematode communities reflecting soil disturbance. Somefree-living nematodes serve as biological models to testsoil condition in the laboratory and because of theseadvantages soil nematodes are increasingly being used asbiological indicators of soil health.

CRISPR/Cas9-introduced single and multiple mutagenesis in strawberry

CRISPR/Cas9-mediated genome editing is a powerful tool for life science research. Recently, strawberry (Fragaria × ananassa), an important horticultural crop, has emerged as a model organism for investigating the regulatory mechanisms of fruit development and ripening (Shulaev et al., 2011; Jia et al., 2013, 2017; Kang et al., 2013; Han et al., 2015). While most cultivated strawberries