coexistence of trichome variation in a natural plant population a combined study using ecological and candidate gene approaches共存的毛状体在天然植物种群变化综合研究生态和候选基因的方法.pdfVIP

Coexistence of Trichome Variation in a Natural Plant Population: A Combined Study Using Ecological and Candidate Gene Approaches 1,2 2 3 4 Tetsuhiro Kawagoe *, Kentaro K. Shimizu , Tetsuji Kakutani , Hiroshi Kudoh 1 Department of Biology, Faculty of Science, Kobe University, Kobe, Japan, 2 Institute of Plant Biology, University of Zurich, Zurich, Switzerland, 3 National Institute of Genetics, Mishima, Shizuoka, Japan, 4 Center for Ecological Research, Kyoto University, Otsu, Japan Abstract The coexistence of distinct phenotypes within populations has long been investigated in evolutionary ecology. Recent studies have identified the genetic basis of distinct phenotypes, but it is poorly understood how the variation in candidate loci is maintained in natural environments. In this study, we examined fitness consequences and genetic basis of variation in trichome production in a natural population of Arabidopsis halleri subsp. gemmifera. Half of the individuals in the study population produced trichomes while the other half were glabrous, and the leaf beetle Phaedon brassicae imposed intensive damage to both phenotypes. The fitness of hairy and glabrous plants showed no significant differences in the field during two years. A similar result was obtained when sibling hairy and glabrous plants were transplanted at the same field site, whereas a fitness cost of trichome production was detected under a weak herbivory condition. Thus, equivalent fitness of hairy and glabrous plants under natural herbivory allows their coexistence in the contemporary population. The pattern of polymorphism of the candidate trichome gene GLABROUS1 (GL1) showed no evidence of long-term maintenance of trichome va