Biology and resource acquisition of mistletoes,and the defense responses of host plants  

作　　者：Meseret Muche A.Muthama Muasya Berhanu Abraha Tsegay 

机构地区：[1]Department of Biology,Woldia University,P.O.Box 400,Woldia,Ethiopia [2]Department of Biological Sciences,University of Cape Town,Ronde-bosch 7700,South Africa [3]Department of Biology,Bahir Dar University,P.O.Box 79,Bahir Dar,Ethiopia

出　　处：《Ecological Processes》2022年第1期332-344,共13页生态过程（英文）

摘　　要：Background:Mistletoes are the most successful group of obligatory hemi-parasitic flowering plants that attach to the host via haustorium for obtaining water and minerals.This review aims to assess the current knowledge on mistle-toes host plant recognition,haustorium formation,water/minerals acquisition,and host plants’defense signaling and responses against mistletoe attack.Results:Some mistletoes are host-specific while others are generalists occurring on a wide range of vascular plants.The host nitrogen(N)content,parasite–host chemical interactions,compatibility,and dispersal agents are the main determinant factors for host specificity.Mistletoes take up substantial amounts of water and minerals passively via apoplastic routes,and most are xylem feeders,but could shift to phloem-feeding during the physiological stress of the host plants.Current evidence highlighted that cell wall loosening and modification are critical during the development of the haustorium in the host tissue.This is made possible by the application of physical pressures by the developing haustorium and cell wall degradation using enzymes(xyloglucan endotransglycosylases,glucanase,expansins,etc.)produced by the mistletoe.Host plants defend against mistletoe infection mechanically by producing spines,lignin,suberin,etc.,which discourages dispersers,and chemically defend by killing the infector or inhibiting the establishment of the haustorium using their secondary metabolites such as terpenes,phenolics,and N-containing compounds.Although the host plants’response to mistletoe attack resembles the response to other biotic stresses,unlike short-term stressors,the effect of mistletoe attack is long-term and depends on the parasite load.Infection by mistletoe leads to water and nutrient stress of the host plant and deteriorates its healthy establishment and survival.Conclusion:Mistletoes are heterogeneous group in the order Santalales which have versatile mechanisms for pollination,seed dispersal and nutrient acquisition from host plants.Inf

关 键 词：Biotic stress HAUSTORIUM Host defense MISTLETOES MIMICRY Resource procurement 

分 类 号：Q94[生物学—植物学]