Sorghum shows strong growth stimulation on arbuscular mycorrhizal (AM) symbiosis, while barley and wheat show growth depression. We identified the AM-inducible phosphate transporter genes of these cereals. Their protein products play major roles in phosphate absorption from arbuscules, intracellular fungal structures. Unexpectedly, barley and wheat expressed the AM-inducible genes at high levels. Hence the cause of their growth depression appears to be unrelated to the transcription of these genes. Notably, fungal vesicles were formed significantly more in barley and wheat than in sorghum. This study yielded new clues for investigation of the mechanism underlying these various responses.

Arbuscular mycorrhizal fungi support the absorption of mineral nutrients by their host plants in exchange for photosynthate. We evaluated the growth responses of 64 rice cultivars to root colonization by an arbuscular mycorrhizal fungus, Funneliformis mosseae, and identified the most positively responsive cultivar as indica rice, ARC5955. We compared the changes of mineral contents of ARC5955 under colonization by the fungus with those of a nonresponsive japonica cultivar, Nipponbare. Colonization increased the contents of beneficial elements such as P and decreased those of deleterious elements such as Cu and Al in both ARC5955 and Nipponbare. However, only ARC5955 showed strong growth stimulation. These results may provide new insights for breeding and yield increase of rice in sustainable agriculture.

Strigolactones (SLs) are plant hormones that control diverse aspects of the shoot and root growth and are exuded into the soil as recruitment signals for arbuscular mycorrhizal (AM) fungi. SL signaling in plants is transduced via the α/β-hydrolase receptor Dwarf14 (D14). The D14 family consists of D14, Dwarf14-like (D14L), and Dwarf14-like 2 (D14L2) clades in rice. The D14L receptor is known to condition pre-symbiotic perception of AM fungi. In this study, it was found that the Dwarf14-like2a ( D14L2a ) gene expression was significantly induced by AM fungal colonization. The transcript of D14L2a appeared not only in mature arbuscule-containing cells but also in epidermal/cortical cells at an early colonization stage and near the elongating intercellular hyphae. D14L2a transcript was detected normally in mycorrhizal roots of str1-2 mutant that form stunted arbuscules, suggesting that the gene expression is independent of arbuscule development. Moreover, the recombinant D14L2a protein exhibited hydrolase activity of synthetic SL, rac -GR24. Based on these results, we discussed the role of D14L2 in the establishment of AM symbiosis.

Seedlings of three rice (Oryza sativa L.) varieties (one indica, ARC5955; and two japonica, Nipponbare and Koshihikari) with or without pre-colonization by the arbuscular mycorrhizal fungus Funneliformis mosseae were transplanted into an upland field and grown to maturity. Pre-colonization had no effect on the yield of Nipponbare or Koshihikari. However, pre-colonized ARC5955 exhibited a strong tendency toward increased yield, which was accompanied by increases in the percentage of ripened grain and the 1000-grain weight. The rice roots were also colonized by indigenous arbuscular mycorrhizal fungi in the field, but these had only limited effects on shoot biomass and grain yields. We speculate that F. mosseae may have exhibited priority effects, allowing it to dominate the rice roots. There was no significant difference in the contents of most mineral elements in the shoots of pre-colonized ARC5955 at harvest, indicating that some other factor is responsible for the observed yield increase.

Vegetable production is an important activity, source of food and income for farmers. Vegetables are grown in many regions in Lao PDR. There is a large range of agro-climatic conditions between the two seasons - wet and dry. The dry season is suitable and favourable for vegetable production. However, the wet season has high temperature, high relative humidity, high soil moisture content and heavy rain. These conditions cause several negative impacts for vegetable production such as, low vegetable productivity and poor quality. Higher application of pesticides can also lead to food safety issues and high input cost of cultivation. These challenges could impact to inadequate domestic supply of vegetables in rainy season, low economic returns from vegetable production, and increased imports of vegetable from other countries. NAFRI and ACIAR have cooperated to research and develop a design of greenhouse structure that is economical and provides suitable growing conditions in the wet season to help farmers to mitigate the multiple constraints and successfully grow vegetables year-round. The new design was constructed and tested with several types of vegetable crops including coriander, lettuce, spring onion and tomato during 2015–2018. Evaluation was made against ambient conditions, crop needs and also a comparison with several other protected cropping designs was conducted. The new design provides improved, cooler and more suitable growing conditions for a range of crops, increasing productivity and quality of vegetable in the wet season.