Identification of S-RNase genotype and analysis of its origin and evolutionary patterns in Malus plants

Identification of the S genotype of Malus plants will greatly promote the discovery of new genes,the cultivation and production of apple,the breeding of new varieties,and the origin and evolution of self-incompatibility in Malus plants.In this experiment,88 Malus germplasm resources,such as Aihuahong,Xishuhaitang,and Reguanzi,were used as materials.Seven gene-specific primer combinations were used in the genotype identification.PCR amplification using leaf DNA produced a single S-RNase gene fragment in all materials.The results revealed that 70 of the identified materials obtained a complete S-RNase genotype,while only one S-RNase gene was found in 18 of them.Through homology comparison and analysis,13 S-RNase genotypes were obtained:S_(1)S_(2)(Aihuahong,etc.),S_(1)S_(28)(Xixian Haitang,etc.),S_(1)S_(51)(Hebei Pingdinghaitang),S_(1)S_(3)(Xiangyangcun Daguo,etc.),S_(2)S_(3)(Zhaiyehaitang,etc.),S_(3)S_(51)(Xishan 1),S_(3)S_(28)(Huangselihaerde,etc.),S_(2)S_(28)(Honghaitang,etc.),S_(4)S_(28)(Bo 11),S_(7)S_(28)(Jiuquan Shaguo),S_(10)S_e(Dongchengguan 13),S_(10)S_(21)(Dongxiangjiao)and S_(3)S_(51)(Xiongyue Haitang).Simultaneously,the frequency of the S gene in the tested materials was analyzed.The findings revealed that different S genes had varying frequencies in Malus resources,as well as varying frequencies between intraspecific and interspecific.S_(3) had the highest frequency of 68.18%,followed by S_(1)(42.04%).In addition,the phylogenetic tree and origin evolution analysis revealed that the S gene differentiation was completed prior to the formation of various apple species,that cultivated species also evolved new S genes,and that the S_(50) gene is the oldest S allele in Malus plants.The S_(1),S_(29),and S_(33) genes in apple-cultivated species,on the other hand,may have originated in M.sieversii,M.hupehensis,and M.kansuensis,respectively.In addition to M.sieversii,M.kansuensis and M.sikkimensis may have also played a role in the origin and evolution of some Chinese apples.

植物氮形态利用策略及对外来植物入侵性的影响

氮是影响外来植物入侵性的重要因素之一,但相关研究多关注土壤氮水平的效应,较少考虑氮形态的作用。为从土壤氮形态利用的角度阐释外来植物的入侵机制,本文在植物氮形态利用策略分析的基础上,综述了外来植物氮形态利用的偏好性及其对入侵性的影响。植物的氮形态利用策略有偏好性和可塑性两种,这可能与植物对土壤氮形态特性的长期适应有关;植物不仅可以对土壤氮形态做出响应,而且还能改造土壤氮形态,并对改变后的土壤氮形态做出反馈响应。很多外来植物入侵硝态氮占优势的干扰生境,偏好硝态氮的外来植物与本地植物竞争硝态氮;而偏好铵态氮的外来植物通过抑制土壤硝化作用,营造铵态氮环境,促进自身生长,同时抑制偏好硝态氮的本地植物生长。然而,植物氮形态利用策略不是一成不变的,而是受多种生物和非生物因素共同作用影响的复杂过程,今后应加强多因素交互作用对外来入侵植物氮形态利用策略的影响及机制研究,更好地揭示氮形态利用策略,尤其是氮形态利用的可塑性与外来植物入侵性的关系。