Sex determination in plants gives rise to unisexual flowers.  A better understanding of the regulatory mechanism underlying the production of unisexual flowers will help to clarify the process of sex determination in plants and allow researchers and farmers to harness heterosis.  Androecious cucumber (Cucumis sativus L.) plants can be used as the male parent when planted alongside a gynoecious line to produce heterozygous seeds, thus reducing the cost of seed production.  The isolation and characterization of additional androecious genotypes in varied backgrounds will increase the pool of available germplasm for breeding.  Here, we discovered an androecious mutant in a previously generated ethyl methanesulfonate (EMS)-mutagenized library of the cucumber inbred line ‘406’.  Genetic analysis, whole-genome resequencing, and molecular marker-assisted verification demonstrated that a nonsynonymous mutation in the ethylene biosynthetic gene 1-AMINOCYCLOPROPANE-1-CARBOXYLATE SYNTHASE 11 (ACS11) conferred androecy.  The mutation caused an amino acid change from serine (Ser) to phenylalanine (Phe) at position 301 (S301F).  In vitro enzyme activity assays revealed that this S301F mutation leads to a complete loss of enzymatic activity.  This study provides a new germplasm for use in cucumber breeding as the androecious male parent, and it offers new insights into the catalytic mechanism of ACS enzymes.

China’s food supply and demand have significant implications for both China’s own national food security and that of the world.  This study reviews China’s food security prospects and their implications, focusing on international trade in the coming decade.  The results show that China’s policies for ensuring food security will be enhanced and China will move to sustainable agriculture.  Most studies anticipate that China will increase its food and feed imports in the coming decade.  China’s overall food self-sufficiency is likely to fall from 94.5% in 2015 to around 91% by 2025.  The greatest increases in imports are likely to be soybean, maize, sugar, and dairy products.  However, within the production capacity of the major exporting countries and of many food-importing developing countries, China’s additional imports of 3 to 5% of its total food consumption in the coming decade are unlikely to threaten global food security.  Indeed, the projected imports of feed and several foods could provide opportunities for many exporting countries to expand their production and save global resources.  

Salt stress is a major environmental factor that inhibits crop growth.  Trichoderma spp. are the most efficient biocontrol fungi and some of the strains can stimulate plant growth.  Phosphate solubilization is known as one of the main mechanisms in promoting plant growth, but the underlying mechanisms of phosphate solubilization in the salinity still need to be explored.  The Trichoderma asperellum Q1 isolated and identified in our lab is a beneficial rhizosphere biocontrol fungus with a high phosphate solubilization activity.  It could produce acid and alkaline phosphatases when using insoluble organic phosphorus as the sole phosphorus source, the salt stress increased the phosphorus-solubilization ability of the strain and the activities of the two enzymes.  Furthermore, an acid phosphatase was purified from the fermentation broth by ammonium sulphate precipitation, ion-exchange, and gel filtration chromatography.  Its molecular weight was 55 kDa as determined by SDS-PAGE.  The purified acid phosphatase was used to investigate growth performance of Arabidopsis thaliana by plate assay and the result showed that it contributed to Arabidopsis growth by transforming organic phosphate into a soluble inorganic form under salt stress.  To our knowledge, this is the first report on acid phosphatase purification from T. asperellum and its function in regulation of plant growth under salt stress.