Rice production is gravely threatened by bacterial leaf streak (BLS). BLS prevention and control rely heavily on chemical pesticides, which contaminate the environment and endanger human health. Here, we evaluated the effects of inducer of plant resistance ZhiNengCong (ZNC), which is derived from endophytic fungi Paecilomyces variotii, the chemical pesticide dioctyl diethylenetriamine (DDL) and the antibiotic pesticide zhongshengmycin (ZSM) on grain size and quality of diseased- rice (DR). BLS significantly reduced the thousand-grain weight and seed setting rate of rice plants, which could be restored by ZNC rather than DDL or ZSM. Transcriptome and metabolomics profiling showed that ZNC increased the expression levels of resistance-, growth- and sugars, amino acids and lipid metabolism-related genes in DR leaves and restored the levels of carbohydrates, vitamins, nucleotides and amino acids in DR grains, which is better than DDL and ZSM. This study demonstrates that plant immune inducers are more effective than conventional pesticides in restoring DR yield and quality, which provides novel insights into the innovation of green biopesticides in sustainable crop production.

Plants have evolved a two-layer immune system comprising pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) that is activated in response to pathogen invasion. Microbial patterns and pathogen effectors can be recognized by surface-localized pattern-recognition receptors (PRRs) and intracellularly localized nucleotide-binding leucine-rich repeat receptors (NLRs) to trigger PTI and ETI responses, respectively. At present, the metabolites activated by PTI and ETI and their roles and signalling pathways in plant immunity are not well understood. In this study, metabolomic analysis showed that ETI and PTI induced various flavonoids and amino acids and their derivatives in plants. Interestingly, both glutathione and neodiosmin content were specifically up-regulated by ETI and PTI, respectively, which significantly enhanced plant immunity. Further studies showed that glutathione and neodiosmin failed to induce a plant immune response in which PRRs/co-receptors were mutated. In addition, glutathione-reduced mutant gsh1 analysis showed that GSH1 is also required for PTI and ETI. Finally, we propose a model in which glutathione and neodiosmin are considered signature metabolites induced in the process of ETI and PTI activation in plants and further continuous enhancement of plant immunity in which PRRs/co-receptors are needed. This model is beneficial for an in-depth understanding of the closed-loop mode of the positive feedback regulation of PTI and ETI signals at the metabolic level.

Potato (Solanum tuberosum L.) is the world’s most important non-grain food crops, so it is important to improve the potato yield and quality. Lipid transfer proteins (LTPs) play critical roles in various environmental stresses. Here, we studied the function of the heterologous overexpression of NtLTP4 from Nicotiana tabacum in potato. We cloned ubiquitin promoter ubi3 from potato, and then constructed the plant expression recombinant plasmid ubi3:pX6–NtLTP4, and transformed it into potato. PCR results indicated that 15 positive plants were obtained. Furthermore, quantitative real-time PCR data showed that 5 plants had high expression level of NtLTP4 gene. Western blot analyses showed that the NtLTP4 gene and its encoded protein (about 12 kDa) were normally transcribed and expressed in potato, indicating that transgenic NtLTP4 potato plants were successfully obtained. The tolerance to salt, drought, and Ralstonia solanacearum of potato plants with NtLTP4 overexpression was enhanced compared with that of non-transgenic plants. The resistance mechanism was also studied by detecting related resistance and functional genes. This study provides a method to improve potato resistance and obtain new transgenic potato varieties.

Coated diammonium phosphate (CDAP) is intended to release nutrients steadily in response to the demand of crop growth. A novel biostimulant extracted from Paecilomyces variotii has been shown to regulate gene expression in nutrient transport, enhance nitrogen (N) and phosphorus (P) uptake, and improve nutrient use efficiency. The application of CDAP combined with the Paecilomyces variotii extracts (ZNC) in maize is an efficient approach for reducing waste of resources, improving nutrient supply, and maintaining production stability. The effects of CDAP combined with ZNC on photosynthesis, enzyme activities, endogenous hormone content, maize yield, and P use efficiency (PUE) were investigated in this study. In a pot experiment, CDAP and diammonium phosphate (DAP) were tested together with P levels (1.80, 1.44 g pot-1, P2O5) and two ZNC application rates (0, 4.4 μg pot-1), which included the control treatment that had no P fertilizer added. Results showed that the key influencing elements of maize growth and yield were the soil available-P content, endogenous hormone content, and plant photosynthesis in this study. The combination of DAP and ZNC increased the soil available-P content and the auxin content in leaves at the key stage and hence increased the yield and PUE of maize, compared with DAP. The net photosynthetic rate of CDAP combined with ZNC was higher by 23.1% than that of CDAP alone, as well as by 32.0% than that of DAP combined with ZNC. Moreover, the combination of CDAP and ZNC increased the yield and PUE by 8.2% and 15.6 percentage points compared with DAP combined with ZNC while increasing the yield and PUE compared with CDAP. In conclusion, combining CDAP with ZNC as an environmentally friendly fertilizer could improve photosynthesis-related enzyme activity and enhance the net photosynthetic rate, resulting in an increase in maize yield and PUE significantly.

Some microbial volatile organic compounds (mVOCs) can act as antagonistic weapons against plant pathogens, but little information is available on the contribution of individual mVOC to biocontrol and how they interact with plant pathogens. In this study, the Bacillus subtilis strain N-18 isolated from the rhizosphere of healthy plants grown in areas where Fusarium crown and root rot (FCRR) of tomato occurs could reduce the 30% of the incidence of FCRR. Moreover, the volatile organic compounds (VOCs) produced by N-18 had inhibitory effects on Fusarium oxysporum f. sp. radicis-lycopersici (FORL). The identification of VOCs of N-18 was analyzed by the solid-phase microextraction coupled to gas chromatography-mass spectrometry. Meanwhile, we conducted sensitivity tests with these potential active ingredients and found that the volatile substances acetoin and 2-heptanol can reduce the 41.33% and 35% of the incidence of FCRR in tomato plants. In addition, the potential target protein of acetoin, found in the cheminformatics and bioinformatics database, was F. oxysporum of hypothetical protein AU210_012600 (FUSOX). Molecular docking results further predicted that acetoin interacts with FUSOX protein. These results reveal the VOCs of N-18 and their active ingredients in response to FORL and provide a basis for further research on regulating and controlling FCRR.

建立了反式玉米素、赤霉素A3、水杨酸、吲哚乙酸、茉莉酸、多效唑、脱落酸、芸苔素内脂和胺鲜酯9种植物生长调节剂含量的高效液相色谱(HPLC)分析方法.肥料样品用甲醇提取,以Venusil XBP C18色谱柱(100 mm×4.6 mm×5μm)分离,流动相为甲醇-水(含0.1％冰HAc),梯度洗脱,选用230 nm和260 nm双波长检测.结果 表明:9种植物生长调节剂在其线性范围内,线性关系良好,相关系数(R2)在0.9985～0.9998之间,加标回收率范围为91.92％～104.68％,相对标准偏差＜5％(n=3).本研究为复合肥、掺混肥等肥料中上述植物生长调节剂的检测提供了可靠的方法.

芸苔素内酯是一类活性较高、广谱、无毒的植物生长调节剂.ZNC免疫诱抗剂是一种新兴的超高活性生物刺激素,具有较强的促生、抗病、抗逆、提高肥料利用率、提高作物产量和品质等功效.本文介绍了植物生长调节剂和生物刺激素的特点、功效,着重分析了芸苔素内酯与ZNC免疫诱抗剂的功效、活性、安全性及作用机理,以期为芸苔素内酯和ZNC免疫诱抗剂的研究应用提供参考.