Phosphorus is an essential macronutrient for plant growth and development, but phosphate resources are limited and rapidly depleting due to massive global agricultural demand. This study identified two genes in the phosphate transporter 2 (PHT2) family of soybean by bioinformatics. The expression patterns of two genes by qRT-PCR at leaves and all were induced by low-phosphate stress. After low-phosphate stress, GmPHT2;2 expression was significantly higher than GmPHT2;1, and the same trend was observed throughout the reproductive period. The result of heterologous expression of GmPHT2 in Arabidopsis knockout mutants of atpht2;1 shows that chloroplasts and whole-plant phosphorus content were significantly higher in plants complementation of GmPHT2;2 than in plants complementation of GmPHT2;1. This suggests that GmPHT2;2 may play a more important role in plant phosphorus metabolic homeostasis during low-phosphate stress than GmPHT2;1. In the yeast backfill assay, both genes were able to backfill the ability of the defective yeast to utilize phosphorus. GmPHT2 expression was up-regulated by a low-temperature treatment at 4 °C, implying that GmPHT2;1 may play a role in soybean response to low-temperature stress, in addition to being involved in phosphorus transport processes. GmPHT2;1 and GmPHT2;2 exhibit a cyclic pattern of circadian variation in response to light, with the same pattern of gene expression changes under red, blue, and white light conditions. GmPHT2 protein was found in the chloroplast, according to subcellular localization analysis. We conclude that GmPHT2 is a typical phosphate transporter gene that can improve plant acquisition efficiency.

Glutathione S-transferases (GSTs)—an especially plant-specific tau class of GSTs—are key enzymes involved in biotic and abiotic stress responses. To improve the stress resistance of crops via the genetic modification of GSTs, we predicted the amino acids present in the GSH binding site (G-site) and hydrophobic substrate-binding site (H-site) of OsGSTU17, a tau class GST in rice. We then examined the enzyme activity, substrate specificity, enzyme kinetics and thermodynamic stability of the mutant enzymes. Our results showed that the hydrogen bonds between Lys42, Val56, Glu68, and Ser69 of the G-site and glutathione were essential for enzyme activity and thermal stability. The hydrophobic side chains of amino acids of the H-site contributed to enzyme activity toward 4-nitrobenzyl chloride but had an inhibitory effect on enzyme activity toward 1-chloro-2,4-dinitrobenzene and cumene hydroperoxide. Different amino acids of the H-site had different effects on enzyme activity toward a different substrate, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole. Moreover, Leu112 and Phe162 were found to inhibit the catalytic efficiency of OsGSTU17 to 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, while Pro16, Leu112, and Trp165 contributed to structural stability. The results of this research enhance the understanding of the relationship between the structure and function of tau class GSTs to improve the abiotic stress resistance of crops.

Cyanobacteria, ubiquitous phototrophic prokaryotes, can enhance soil fertility and crop productivity by promoting biological nitrogen fixation, phosphate dissolution, and mineral release. In this study, five nitrogen-fixing cyanobacteria were isolated and purified from paddy soil in Jilin Province. The effects of nitrogen-fixing cyanobacteria on soil fertility and rice seedling growth were examined through a pot experiment to clarify their growth and nitrogen-fixing characteristics. The results showed that the application of nitrogen-fixing cyanobacteria led to a significant increase in soil nitrogen content. GD2 and GD8 have the highest nitrogenase activity, at 75.33 U·mg⁻¹ and 50.34 U·mg⁻¹, respectively. It also enhanced the activities of urease, sucrase, phosphatase, and catalase in rice soil. In addition, it significantly promoted root development and plant height in rice plants. The total number of microorganisms in rice soil increased by 133–366%. Remarkably, the Desmonostoc muscorum GD2 strain was found to exhibit higher growth state indicators, including the growth curve, chlorophyll content, carbon and nitrogen content, and biomass accumulation, compared to other algae strains. The total nitrogen content of rice leaves treated with GD2 increased by 48.73%, and the soluble protein content increased by 52.89%. GD2 has great potential as an excellent nitrogen-fixing cyanobacteria inoculant for rice, suitable for agricultural production. In conclusion, the application of these nitrogen-fixing cyanobacteria significantly increased soil nitrogen levels and activated key enzyme activities involved in plant nitrogen metabolism. Moreover, it improved nitrogen utilization rates and promoted plant growth.

There is still limited information on how genetic introgression impacts morphological variation and population fitness in long-lived conifer species. Two closely related pine species, Pinus kesiya Royle ex Gordon and Pinus yunnanensis Franch. are widely distributed over Southeast Asia and Yunnan province of China, with a large spatial scale of asymmetric genetic introgression and hybridization, and form a hybrid lineage, P. kesiya var. langbianensis, where their ranges overlap in southeast Yunnan. We compared seed trait variation and germination performance between hybrids and parental species and characterized environmental gradients to investigate the genetic and ecological evolutionary consequences of genetic introgression. We found that seed width (SW) differed significantly among the three pines, and all the seed traits were significantly negatively correlated with latitude and associated with the mean temperatures of the driest and wettest quarters. A higher germination fitness of hybrids was detected at a low temperature, indicating that they had better adaptability to temperature stress than their parental species during the germination process. Our results suggest that environmental factors shape seed phenotypic variation in the pine species and that genetic introgression significantly affects seed germination fitness. Therefore, assisting gene flow in natural forest populations might facilitate their adaptation to climate change.