根腫菌侵染莖瘤芥不同時期效應子基因表達動態分析

摘 要：效應子在病原菌侵染植物過程中扮演著重要角色，為明確效應子在根腫菌侵染莖瘤芥過程中的功能，首先通過qRT-PCR對效應子基因在侵染不同時期的表達量進行分析，從而對根腫菌中效應子進行分類鑒定，然后利用TBtools對效應子蛋白進行結構域分析，以期明確效應子所具備的功能。結果表明：根腫菌中的效應子包含LxAR類效應子13個、RxLR類效應子13個和其余未分類效應子66個；其中，LxAR類效應子的表達量在根腫菌侵染莖瘤芥的0周和5周較高，說明其主要在休眠孢子階段和孢子成熟階段起作用；RxLR類效應子中，RxLR1類在根腫菌侵染莖瘤芥的3～5周表達量較高，主要在皮層侵染期起作用，RxLR2類在根腫菌侵染莖瘤芥的0周表達量較高，主要在休眠孢子期起作用。由此推測，LxAR和RxLR類效應子可能分別在促進生長發育和控制基因表達、抑制酶活等方面有功能。

關鍵詞：莖瘤芥；根腫病；蕓薹根腫菌；效應子；基因表達

中圖分類號：S482.4 文獻標識碼：A 文章編號：1006-060X（2023）07-0001-10

Abstract：As one of the main diseases of cruciferous crops， clubroot sharply reduces the yield of cruciferous crops and causes huge economic losses. Effector gene plays an important role for a pathogen infecting hosts. To clarify the function and role of effectors in the process of Plasmodiophora brassicae infecting tuber mustard （Brassica juncea var. tumida）， the expression of different types of effector genes in different stages of infection was quantitatively analyzed by qRT-PCR; furthermore， according to the characteristic conserved sequence motifs and sequence alignment， the effectors were classified and identified; and Tbtools was used for functional analysis on domains of the effector proteins. The results showed that the effectors in Plasmodiophora brassicae were divided into 13 LxAR effectors， 13 RxLR effectors and 66 unclassified effectors. The expression of LxAR effector genes was high in 0 and 5th week of the infecting process， indicating that these genes played a role in resting spore stage and spore maturation stage. Of RxLR effectors， RxLR1 expressed high in 3-5 weeks of the infecting process， mainly playing a role in cortex infection stage; RxLR2 expressed high in 0 week of the infecting process， mainly playing a role at resting spore stage. Thereforce， it is speculated that LxAR and RxLR effectors possibly function in promoting growth and development， controlling gene expression and inhibiting enzyme activity.

Key words：tuber mustard （Brassica juncea var. tumida）; clubroot disease; Plasmodiophora brassicae; effector; gene expression

莖瘤芥（Brassica juncea var. tumida Tsen et Lee）又名青菜頭、菜頭，是一種以瘤狀膨大莖供食用的十字花科蕓薹屬蔬菜，既可鮮食又可腌制加工，是加工榨菜的原材料[1]。根腫病嚴重影響涪陵地區莖瘤芥的生產，常給種植戶帶來巨大的經濟損失[2]。蕓薹根腫菌（Plasmodiophora brassicae Woron）是引起根腫病的病原菌，它寄生于十字花科植物根部，使根部膨大形成腫瘤，影響植物水分和養分吸收，導致地上部萎蔫或死亡[3-4]。根腫菌是一種介于粘菌和真菌之間的土傳專性活體寄生菌，在土壤中具有很強的存活能力，導致根腫病的防治極為困難[5-6]。……