Drought stress can reduce strawberry yield and quality and is one of the main abiotic factors restricting strawberry production in China. Nano-agricultural technology has significant regulatory effects in improving crop yield and quality and reducing agricultural environmental pollution. We performed a pot experiment using FenYu No. 1 strawberry and applied copper nanoparticles (CuNPs) and selenium NPs (SeNPs) to study their effects on the growth, quality, photosynthetic parameter indexes, and physiological characteristics of strawberry plants under drought stress. The growth and photosynthesis of strawberry plants were significant adversely affected by moderate drought stress (DS, 60% field capacity (FC)) and severe drought stress (SS, 25% FC). Compared with normal water-holding conditions, the application of CuNPs, SeNPs, and their combination effectively increased the agronomic traits of strawberry plants; improved fruit quality; and enhanced the content of photosynthetic pigments (chlorophyll a, chlorophyll b, and total chlorophyll), photosynthetic characteristic parameters, chlorophyll fluorescence parameters, and water-use efficiency. In addition, the exogenous application of CuNPs and SeNPs improved the drought tolerance of plants by increasing the activities of antioxidant enzymes catalase, peroxidase, and superoxide dismutase, and decreasing the malondialdehyde content, with the following overall trend among the treatments: control < CuNPs < SeNPs < CuNPs + SeNPs. The results of the principal component analysis showed that the two extracted principal components could reflect 85.54% of the information of the original data, leaf photosynthetic pigments, photosynthetic characteristic parameters, chlorophyll fluorescence parameters, and strawberry agronomic traits indexes and could be used as the primary indexes for evaluating the improvement of strawberry growth by nanofertilizers under drought-stress conditions. Taken together, our results indicate that nanofertilizers have potential for improving the growth, quality, and physiological characteristics of strawberries under drought stress.

Gibberellins (GAs) are diterpenoid phytohormones regulating various aspects of plant growth and development, such as internode elongation and seed germination. Although the GA biosynthesis pathways have been identified, the transcriptional regulatory network of GA homeostasis still remains elusive. Here, we report the functional characterization of a GA-inducible OsABF1 in GA biosynthesis underpinning plant height and seed germination. Overexpression of OsABF1 produced a typical GA-deficient phenotype with semi-dwarf and retarded seed germination. Meanwhile, the phenotypes could be rescued by exogenous GA₃, suggesting that OsABF1 is a key regulator of GA homeostasis. OsABF1 could directly suppress the transcription of green revolution gene SD1, thus reducing the endogenous GA level in rice. Moreover, OsABF1 interacts with and transcriptionally antagonizes to the polycomb repression complex component OsEMF2b, whose mutant showed as similar but more severe phenotype to OsABF1 overexpression lines. It is suggested that OsABF1 recruits RRC2-mediated H3K27me3 deposition on the SD1 promoter, thus epigenetically silencing SD1 to maintain the GA homeostasis for growth and seed germination. These findings shed new insight into the functions of OsABF1 and regulatory mechanism underlying GA homeostasis in rice.

Polyploidy has pivotal influences on rice (Oryza sativa L.) morphology and physiology, and is very important for understanding rice domestication and improving agricultural traits. Diploid (DP) and triploid (TP) rice shows differences in morphological parameters, such as plant height, leaf length, leaf width and the physiological index of chlorophyll content. However, the underlying mechanisms determining these morphological differences are remain to be defined. To better understand the proteomic changes between DP and TP, tandem mass tags (TMT) mass spectrometry (MS)/MS was used to detect the significant changes to protein expression between DP and TP. Results indicated that both photosynthesis and metabolic pathways were highly significantly associated with proteomic alteration between DP and TP based on biological process and pathway enrichment analysis, and 13 higher abundance chloroplast proteins involving in these two pathways were identified in TP. Quantitative real-time PCR analysis demonstrated that 5 of the 13 chloroplast proteins ATPF, PSAA, PSAB, PSBB and RBL in TP were higher abundance compared with those in DP. This study integrates morphology, physiology and proteomic profiling alteration of DP and TP to address their underlying different molecular mechanisms. Our finding revealed that ATPF, PSAA, PSAB, PSBB and RBL can induce considerable expression changes in TP and may affect the development and growth of rice through photosynthesis and metabolic pathways.

The use of organic fertilizers instead of chemical fertilizers can improve soil pH, help to maintain soil health and enable landowners to achieve organic or ecological-status agriculture. Rapeseed cake, sheep manure, and biofungal fertilizer are considered to be effective amendments to improve soil quality. However, there have been few studies on the effects of the three fertilizers on strawberry production, soil physicochemical properties, and inter-root soil microbial community structure. In this study, field experiments were conducted to investigate the differences in strawberry growth, quality, yield, and the structure and diversity of strawberry soil bacterial and fungal communities under four treatments: no organic fertilizer (CK), rapeseed cake organic fertilizer (T1), sheep manure organic fertilizer (T2) and bio-organic fertilizer (algae-optimized bacteria) (T3), the relationship between soil physicochemical properties and soil microbial diversity were analyzed. Our results have shown that these three amendments promoted the growth of strawberry to some extent. The effects of available phosphorus, ammonium nitrogen, sucrase, protease and urease under T2 treatment were significantly increased by 50.62%, 54.14%, 276.50%, 129.47%, 232.61%, and 232.00%, respectively, compared with the control. The soil bacterial and fungi community were the most abundant and diversified under the T2 treatment. Soil physicochemical properties and soil key enzyme activities varied significantly under different fertilizer treatments, with the soil nutrient content and soil carbon and nitrogen metabolizing enzyme activities being highest under T2 treatment. A Pearson correlation analysis showed that soil organic matter was closely related to the diversity of soil microbial communities. A redundancy analysis (RDA) showed that the main variables of the bacterial community included nitrate nitrogen (NN) and rapidly available potassium (RAP), while the main variables of the fungal community included alkaline dissolved nitrogen (ADN) and ammonium nitrogen (AN). Overall, different fertilizers promoted the release and transformation of soil nutrients by affecting the structure and diversity of bacterial and fungal communities in strawberry soils, which was beneficial to the supply of soil nutrients and the improvement of soil quality. The application of sheep manure organic fertilizer had the best soil improvement effect.

Anthracnose is a devastating fungal disease in strawberry nurseries. Multiple Colletotrichum species are responsible for strawberry anthracnose. In this study, 105 Colletotrichum isolates were obtained from strawberry seedlings with anthracnose symptoms in fifteen nurseries located in Zhejiang province, China, and were classified based on multilocus sequence and morphological characteristic analyses. Analysis of ITS, ACT, CAL, CHS-1, and GAPDH revealed that four species within C. gloeosporioides species complex, including C. siamense (56 isolates, 53.3%), C. fructicola (37 isolates, 35.2%), C. gloeosporioides (7 isolates, 6.7%), and C. aenigma (5 isolates, 4.8%), were detected in diseased seedlings. Thiophanate-methyl is one of the benzimidazole fungicides, and has long been used to control strawberry anthracnose in China. Here, thiophanate-methyl resistance of Colletotrichum isolates was determined by the minimum inhibitory concentration (MIC) method. Our results indicated that the resistance frequency was up to 96.2%, containing 94.3% of highly resistant isolates. Only four sensitive isolates (two C. fructicola, one C. gloeosporioides, and one C. siamense isolates) and two moderately resistant isolates (one C. aenigma isolate and one C. siamense isolate) were detected. Our data indicated that the high resistance was mainly caused by the E198A mutation in the β-tubulin protein. In addition, F200Y (TTC→TAC) in the β-tubulin protein were detected in two moderately resistant isolates. Based on the point mutation at codon 198 (GAG→GCG) in the β-tubulin gene of Colletotrichum isolates, we developed a loop-mediated isothermal amplification (LAMP) assay to rapidly detect the E198A mutants. Collectively, our study indicated that four species within the C. gloeosporioides species complex were associated with anthracnose symptoms in strawberry nurseries in Zhejiang province, and serious resistance was widespread in each Colletotrichum species.

Strawberry crown rot poses a significant menace to strawberry production during the seedling stage, and the main pathogen is Colletotrichum spp. Pyraclostrobin is one of the main fungicides that have been registered to control anthracnose caused by Colletotrichum spp. The diversity of pathogens and the risk of fungicide resistance may change from year to year. In order to explore the diversity of pathogens causing crown rot and evaluate the resistance risk of pathogens to pyraclostrobin in different years, crown rot samples were collected in Jiande, Zhejiang Province in 2019 and 2021, and the pathogens were identified. Based on the morphological identification and phylogenetic analysis based on ACT, CAL, CHS, GAPDH, and ITS, all 55 strains were identified as C. gloeosporioides species complexes, including 23 C. siamense isolates and 2 C. fructicola isolates in 2019, and all isolates were identified as C. siamense in 2021. C. siamense was the dominant pathogen of strawberry crown rot in 2019 and 2021. The resistance frequencies of the isolates collected in 2019 and 2021 to pyraclostrobin were 69.57% and 100%, respectively. In general, compared to that in 2019, the resistance frequencies of the pathogen to pyraclostrobin increased in 2021. In terms of fitness, there was no significant difference between resistant strains and sensitive strains in the mycelium growth rate, sporulation and spore germination rate. In addition, the resistant mutants exhibited positive cross-resistance to kresoxim-methyl and azoxystrobin. A sequential analysis of cytochrome b gene showed that C. siamense resistance to pyraclostrobin is linked to the G143A point mutation. Our study indicated that the risk of resistance a fungicide gradually increases with the increase in use years, and in order to reduce the emergence and spread of resistant populations, we should choose fungicides of different mechanisms of action for rotation to reduce the risk of resistance development.