Soft rot caused by Botryosphaeria dothidea leads to massive economic losses in the kiwifruit industry. Natamycin is a natural antimicrobial preservative that effectively prevents postharvest decay and preserves fruit quality. However, the ability to control kiwifruit soft rot and potential antifungal mechanisms have not been explored. In this study, the inhibitory impact of natamycin against soft rot caused by B. dothidea, as well as its putative action mechanisms were investigated. The results indicated that 2 mg L?1 natamycin effectively inhibited mycelial growth and spore germination of B. dothidea in vitro. Natamycin caused B. dothidea hypha to shrink and deform, along with vacuolation and plasmolysis in hypha cells, as observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Likewise, natamycin stimulated the accumulation of reactive oxygen species (ROS) in the hypha. The inhibition effect of natamycin on B. dothidea inoculated in kiwifruit was dose-dependent, with 500 mg L?1 natamycin significantly decreasing the incidence of soft rot to 35%. Furthermore, natamycin induced disease resistance in kiwifruit tissue by activating the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), increasing the antioxidant compound total phenol, maintaining a low level of malondialdehyde (MDA), and repressing the activity of four cell wall degrading enzymes, as well as gene expression of β-galactosidase (β-Gal) and polygalacturonase (PG). Further field research revealed that pre-harvest treatment combined with the postharvest natamycin application significantly reduced the natural decay incidence of kiwifruit while having no negative effect on soft-ripe quality. In conclusion, our findings proved that natamycin has an antifungal effect on B. dothidea and may be applied as a safe preservative to reduce soft rot.

▲golden kiwifruit vine

多蒂葡萄孢菌引起的軟腐病給獼猴桃產(chǎn)業(yè)造成了巨大的經(jīng)濟(jì)損失。納他霉素是一種天然抗菌防腐劑，可有效防止采后腐爛，保持水果質(zhì)量。然而，控制獼猴桃軟腐病的能力和潛在的抗真菌機(jī)制尚未探索。在本研究中，研究了納他霉素對(duì)由點(diǎn)孢雙歧桿菌引起的軟腐病的抑制作用及其可能的作用機(jī)制。結(jié)果表明，2 mg L?1.納他霉素在體外能有效抑制點(diǎn)孢雙歧桿菌的菌絲生長(zhǎng)和孢子萌發(fā)。掃描電子顯微鏡（SEM）和透射電子顯微鏡（TEM）觀察到，納他霉素引起點(diǎn)孢雙歧桿菌菌絲收縮和變形，以及菌絲細(xì)胞中的空泡化和質(zhì)壁分離。同樣，納他霉素刺激菌絲中活性氧的積累。納他霉素對(duì)接種在獼猴桃上的B.dothidea的抑制作用呈劑量依賴(lài)性，劑量為500 mg L?1納他霉素顯著降低軟腐病發(fā)病率至35%。此外，納他霉素通過(guò)激活抗氧化酶超氧化物歧化酶（SOD）和過(guò)氧化氫酶（CAT），增加抗氧化化合物總酚，維持低水平的丙二醛（MDA），抑制四種細(xì)胞壁降解酶的活性，誘導(dǎo)獼猴桃組織的抗病性，以及β-半乳糖苷酶（β-Gal）和多聚半乳糖醛酸酶（PG）的基因表達(dá)。進(jìn)一步的田間研究表明，采前處理結(jié)合采后施用納他霉素顯著降低了獼猴桃的自然腐爛率，同時(shí)對(duì)軟熟品質(zhì)沒(méi)有負(fù)面影響。綜上所述，我們的研究結(jié)果證明納他霉素對(duì)點(diǎn)孢雙歧桿菌具有抗真菌作用，可以作為一種安全的防腐劑來(lái)減少軟腐病。

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▲紅心獼猴桃▲

▲獼猴桃▲

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▲kiwifruit▲

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▲Golden kiwifruit▲

 

▲Kiwi sapling▲

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▲Kiwifruit planting▲

▲Kiwi orchard▲