MIR390 Is Involved in Regulating Anthracnose Resistance in Apple

Abstract

As an important cash crop in China, apple has a good flavor and is rich in nutrients. Fungal attacks have become a major obstacle in apple cultivation. Colletotrichum gloeosporioides is one of the most devastating fungal pathogens in apple. Thus, discovering resistance genes in response to C. gloeosporioides may aid in designing safer control strategies and facilitate the development of apple resistance breeding. A previous study reported that ‘Hanfu’ autotetraploid apple displayed higher C. gloeosporioides resistance than ‘Hanfu’ apple, and the expression level of mdm-MIR390b was significantly upregulated in autotetraploid plants compared to that in ‘Hanfu’ plants, as demonstrated by digital gene expression (DGE) analysis. It is still unclear, however, whether mdm-MIR390b regulates apple anthracnose resistance. Apple MIR390b was transformed into apple ‘GL-3′ plants to identify the functions of mdm-MIR390b in anthracnose resistance. C. gloeosporioides treatment analysis indicated that the overexpression of mdm-MIR390b reduced fungal damage to apple leaves and fruit. Physiology analysis showed that mdm-MIR390b increased C. gloeosporioides resistance by improving superoxide dismutase (SOD) and peroxidase (POD) activity to alleviate the damage caused by O2− and H2O2. Our results demonstrate that mdm-MIR390b can improve apple plants’ anthracnose resistance.

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“…Recently, overexpression of miR391 in TG Arabidopsis lines demonstrated post-transcriptional silencing of the ACA-10 gene by this miRNA(Attri et al 2022). mir390, already known to be functionally important for many years(Fahlgren et al 2006;Hunter et al 2006), has recently been implicated in anthracnose resistance in apples(Shi et al 2022). miR169's role as a negative regulator in rice immunity against the blast fungus by repressing the expression of nuclear factor Y-A genes was con rmed recently(Song et al 2018).…”