Ying Yang,Laifeng Lu,Dandan Sun,Jinghao Wang,Nifei Wang,Liping Qiao,Qingbin Guo,Changlu Wang
Fruit softening exacerbates mechanical damage incurred during shipping and handling and the increase in pathogen susceptibility. Here, oligogalacturonides (OGs) produced by fungal polygalacturonase (PG) delayed fruit softening in tomato and maintained fruit firmness at 8.37 ± 0.45 N at 13 d of storage, which was consistent with the fruit firmness level of 5 d in the control groups. From RNA sequencing data in line production of phytohormones, we confirmed ethylene and jasmonic acid signals, the MAPK signaling cascade, and calmodulin involved in the OG-mediated firmness response of whole fruit. SlPG2, SlPL3, and SlPL5 were the major contributing factors for fruit softening, and their expression decreased continuously upon OG application. Suppression of the expression of ethylene response factors using a virus-induced gene-silencing strategy revealed that SlERF6 was negatively involved in OG-restrained fruit softening. Taken together, these results indicated that fungal PG-generated OGs have potential application value in controlling tomato fruit softening.
Mechanical wounding causes significant economic losses of fresh produce due to accelerated senescence and spoilage as well as loss of nutritional value. Here, pre-application of oligogalacturonides (OGs) enzymatically hydrolyzed from apple pectin effectively reduced the healing times of mechanical wounds from>24 h in mock groups to 12 h, and the Botrytis cinerea infection rate was reduced from 37.5% to 12.5%. OGs accordingly increased callose deposition; SlPR1, SlPAL and SlHCT gene expression; and phenylalanine ammonia-lyase (PAL) activity around the wounds. Inhibition of Ca 2+ signaling using the inhibitor Ruthenium Red markedly inhibited OG accelerated healing of mechanical wounding on fruit. SlPG2, SlEXP1 , and SlCEL2 mRNAs accumulation was reduced in OG-elicited tomato fruit compared to water-treated fruit with subsequent retardation of the fruit softening during ripening. These results indicated that apple pectin OGs accelerate wound healing and inhibit fruit softening by activating calcium signaling in tomato fruits during postharvest storage.
危险品化学品经营许可证（带存储）