| Peach is one of the popular fruits with high nutritional and economic value.In the past decade,peach shoot blight has gradually spread in peach producing areas in southern China,seriously affecting the healthy development of the peach industry.Research has shown that the main pathogen causing peach shoot blight in China is Phomopsis amygdali.As of now,there are no specific drugs for the prevention and control of peach shoot blight and the widespread use of chemical pesticides has led to the development of resistance and posed a threat to the environment and human health.Therefore,it is necessary to study the infection mechanism of peach shoot blight at the molecular level,providing potential targets for the development of efficient and low toxicity specific fungicides.The whole genome sequencing of Phomopsis amygdali ZN32 mold was carried out.The ZN32 genome size was 52.76 Mbp,with a G+C content of 51.90%and 42498 exons and 27076 introns,containing 15422 gene coding proteins.The ZN32 strain contains 181 tRNAs,48 rRNAs,63 sRNAs,39 snRNAs,and 100 miRNAs,the tandem repeat sequence has a total of 1624999 bp,accounting for 3.1578%of the genome.The collinearity analysis of the whole genome sequence of ZN32 with Fusarium graminearum PH-1、Colletotrichum gloeosporioides、Magnaporthe oryzae showed that ZN32 and F.graminearum PH-1 and C.gloeosporioides genome wide nucleic acid collinearity is high.Mitogen-activated protein kinase(MAP kinase)cascades are important mediators of signal transduction.These cascades contain at least three protein kinases in series,and ultimately activate multifunctional MAP kinase.MAP kinase plays a crucial role in regulating many cellular processes,such as controlling embryogenesis,cell differentiation,cell proliferation,and apoptosis.Through BLAST comparison,it was found that there are three MAP kinase signaling pathways in ZN32,namely PaPmkl,PaMps1,and PaOsml MAP kinase signaling pathways.The PaMps1 MAP kinase signaling pathway includes MAP kinase kinase kinase(MEKK)PaMckl,MAP kinase kinase(MEK)PaMkk1,and MAP kinase PaMps1;The PaPmkl MAP kinase signaling pathway includes MEK PaMst7,MAP kinase PaPmk1,and connector protein PaMst50;The PaOsm1 MAP kinase signaling pathway includes MEKK PaSsk2,MEK PaPbs2,and MAP kinase PaOsm1.In P.amygdali,PaPmkl MAP kinase signaling pathway is involved in regulating growth.asexual reproduction,and pathogenicity,and is highly sensitive to salt stress,osmotic stress,and cell wall stress.The absence of PaMST7 and PaPMK1 results in significant inhibition of the vegetative growth rate of P.amygdali,abnormal colony morphology,and reduced pathogenicity.After 30 days of growth in PDA medium,it cannot produce pycnidium and conidia.Mst50,as a connector protein,also plays an important role in the Pmk1 MAP kinase signaling pathway.ΔPamst50 exhibits similar defects in growth,development,and pathogenesis to ΔPammk1,and the SAM and RA domains of PaMst50 play an indispensable role in its growth,development,and pathogenesis.ΔPamck1,ΔPamkk1,and ΔPampsl are highly sensitive to cell wall stress caused by CFW,and their nutritional growth is inhibited.After 30 days of growth in PDA medium,they cannot produce pycnidium and conidia,and their pathogenicity is significantly reduced.PaOsml MAP kinase signal pathway is not involved in the pathogenesis and asexual reproduction of P.amygdali,but is highly sensitive to osmotic stress.In summary,this paper has sequenced the whole genome of P.amygdali ZN32 strain,found the relevant components of the MAP kinase signal pathway and identified the functional role of the MAP kinase signal pathway in P.amygdali.Among them,PaPmk1 MAP kinase signal pathway and PaMps1 MAP kinase signal pathway are involved in regulating growth,asexual reproduction,pathogenicity,and response to stress environment.The PaOsml MAP kinase signaling pathway is mainly involved in the response to high osmotic stress,and has no significant impact on the pathogenicity of peach stem spot mold. |
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