To explore the effect of vermicompost on the yield and quality of tomato cultivated in salty soil, we investigated the soil chemical properties, the yield, vitamin C, organic acid, soluble solids, and nitrate of fruit, photosynthesis, and carbohydrates of plants grown under various salt levels applied with the application of either commercial chemical fertilizers, cow manure, or vermicompost. Results showed that the tomato yield was not increased from the chemical fertilizer application, while there was an increase from the cow manure and vermicompost (increased 31.7% and 65.2%, respectively) under salt stress. Compared to no salt stress, the contents of vitamin C, organic acid, soluble solids, and nitrate increased 26.55%, 40.59%, 46.31%, and 35.08%, respectively, under salt stress (2 g NaCl·kg⁻¹ soil). Compared with the Control, the application of chemical fertilizers failed to improve the sugar/acid ratio but increased nitrate content, while cow manure and vermicompost improved the sugar/acid ratio by 42.0% and 73.1%, respectively. Particularly, vermicompost increased vitamin C and reduced nitrate to the greatest extent among the different fertilizer treatments. The decrease in sodium (Na⁺) in the roots and leaves, increase in carbohydrates in fruit, and photosynthetic efficiency of leaves imply an amendment effect of vermicompost on salt stress. Moreover, vermicompost also facilitated the transit of carbohydrates from leaves to fruits by increasing the accumulation of nitrogen, phosphate, and potassium in fruits, leaves, and roots, while decreasing proline and soluble protein accumulation in leaves and roots. In conclusion, vermicompost could alleviate the adverse effect of salt stress and improve tomato yield and fruit quality by improving the photosynthetic capacity and promoting carbohydrate transport to fruit. The findings give a new perspective on the beneficial effect of vermicompost on tomato yield and quality.

Root-knot nematodes are the major diseases in protected cultivation around the world. Bio-organic fertilizer has become a research hotspot, with a variety of microorganisms that control various vegetable soil-borne diseases. This study screened nematocidal microorganisms from fresh vermicompost, explored the inhibitory substances produced by biocontrol agents, and evaluated their potential biocontrol ability in the pot and field under greenhouse conditions. The highly effective antagonistic microbes of Meloidogyne incognita (M. incognita) were screened. Strains YL1 and YL31 were identified as Peribacillus frigoritolerans, and strain YL6 was identified as Lysinibacillus fusiformis. The three strains all produced chitinase and protease, which prevented the normal development of eggs and the second-stage juveniles (J2) by destroying their appearance. The three strains all improved potassium-dissolving ability, and the strains YL1 and YL6 also enhanced phosphorus-dissolving ability. Pot experiments showed that tomato root knots were reduced, and plant growth improved. Field tests showed that the root-knot index and nematode population were reduced significantly, and cucumber growth and yield were enhanced. Strain YL1 had the best control effect with 70.6%, and the yield increased by 14.9% compared with the control. Overall, this study showed the ability of antagonistic bacteria YL1, YL6, and YL31 to control root-knot nematodes, and these antagonistic bacteria could be developed as biocontrol agents for sustainable agriculture.

Researchers have described protection mechanisms against the photoinhibition of photosystems under strong-light stress. Cyclic Electron Flow (CEF) mitigates electron acceptor-side limitation, and thus contributes to Photosystem I (PSI) protection. Chloroplast protease removes damaged protein to assist with protein turn over, which contributes to the quality control of Photosystem II (PSII). The PGR5 protein is involved in PGR5-dependent CEF. The FTSH protein is a chloroplast protease which effectively degrades the damaged PSII reaction center subunit, D1 protein. To investigate how the PSI photoinhibition phenotype in pgr5 would be affected by adding the ftsh mutation, we generated double-mutant pgr5ftsh via crossing, and its phenotype was characterized in the green algae Chlamydomonas reinhardtii. The cells underwent high-light incubation as well as low-light incubation after high-light incubation. The time course of Fv/Fm values in pgr5ftsh showed the same phenotype with ftsh1-1. The amplitude of light-induced P700 photo-oxidation absorbance change was measured. The amplitude was maintained at a low value in the control and pgr5ftsh during high-light incubation, but was continuously decreased in pgr5. During the low-light incubation after high-light incubation, amplitude was more rapidly recovered in pgr5ftsh than pgr5. We concluded that the PSI photoinhibition by the pgr5 mutation is mitigated by an additional ftsh1-1 mutation, in which plastoquinone pool would be less reduced due to damaged PSII accumulation.