Floral volatile alleles can contribute to pollinator-mediated reproductive isolation in monkeyflowers (Mimulus).
Floral volatile alleles can contribute to pollinator-mediated reproductive isolation in monkeyflowers (Mimulus).
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DOI：
10.1111/tpj.12702
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发表时间：
2014-12
期刊：
影响因子：
--
通讯作者：
Bradshaw HD Jr
中科院分区：
文献类型：
--
作者：
Byers KJ;Vela JP;Peng F;Riffell JA;Bradshaw HD Jr
传粉媒介介导的生殖隔离是推动显花植物多样化的主要因素。有关生殖隔离的花特征的研究几乎完全集中在视觉信号上，如花的颜色。不太明显的信号，如花香，只是最近才被研究。特别是，花挥发性物质参与介导差异传粉者访问的遗传学仍然未知。熊蜂授粉的Mimulus lewisii和蜂鸟授粉的M.红雀是研究通过传粉者偏好生殖隔离的模式系统。我们已经表明，这两个物种在三个花萜类挥发物-D-柠檬烯，β-月桂烯和E-β-罗勒烯-是有吸引力的熊蜂授粉。通过遗传作图和体外酶活性分析，我们证明这些种间差异与两个位点的等位基因变异一致-柠檬烯-月桂烯合酶（LMS）和洋甘菊烯合酶（OS）。M. lewisii LMS（MlLMS）和OS（MlOS）在花发育的最后阶段在花组织中表达最强。M. Cardinalis LMS（McLMS）弱表达，并且在外显子3中具有无义突变。M. cardinalis OS（McOS）的表达与MlOS类似，但编码的McOS酶不产生E-β-罗勒烯。重新概括一下M。cardinalis表型通过RNAi降低MlLMS在转基因M. lewisii在授粉熊蜂中不产生行为差异;然而，减少MlOS表达产生6%的访问减少。在OCIMENE SYNTHASE位点的等位基因变异可能有助于差异传粉访视，从而促进M。lewisii和M.红雀。在开花植物中，OCIMENE SYNTHASE加入了一个不断增长的“物种形成基因”（“屏障基因”）的名单。
Pollinator-mediated reproductive isolation is a major factor in driving the diversification of flowering plants. Studies of floral traits involved in reproductive isolation have focused nearly exclusively on visual signals, such as flower color. The role of less obvious signals, such as floral scent, has been studied only recently. In particular, the genetics of floral volatiles involved in mediating differential pollinator visitation remains unknown. The bumblebee-pollinated Mimulus lewisii and hummingbird-pollinated M. cardinalis are a model system for studying reproductive isolation via pollinator preference. We have shown that these two species differ in three floral terpenoid volatiles - D-limonene, β-myrcene, and E-β-ocimene - that are attractive to bumblebee pollinators. By genetic mapping and in vitro enzyme activity analysis we demonstrate that these interspecific differences are consistent with allelic variation at two loci – LIMONENE-MYRCENE SYNTHASE (LMS) and OCIMENE SYNTHASE (OS). M. lewisii LMS (MlLMS) and OS (MlOS) are expressed most strongly in floral tissue in the last stages of floral development. M. cardinalis LMS (McLMS) is weakly expressed and has a nonsense mutation in exon 3. M. cardinalis OS (McOS) is expressed similarly to MlOS, but the encoded McOS enzyme produces no E-β-ocimene. Recapitulating the M. cardinalis phenotype by reducing the expression of MlLMS by RNAi in transgenic M. lewisii produces no behavioral difference in pollinating bumblebees; however, reducing MlOS expression produces a 6% decrease in visitation. Allelic variation at the OCIMENE SYNTHASE locus likely contributes to differential pollinator visitation, and thus promotes reproductive isolation between M. lewisii and M. cardinalis. OCIMENE SYNTHASE joins a growing list of “speciation genes” (“barrier genes”) in flowering plants.
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影响因子：
3
作者：
Chess, Sally K. R.;Raguso, Robert A.;LeBuhn, Gretchen
通讯作者：
LeBuhn, Gretchen
影响因子：
2.1
作者：
Castellanos, MC;Wilson, P;Thomson, JD
通讯作者：
Thomson, JD
影响因子：
5.3
作者：
Gupta, Alok K.;Akhtar, Tariq A.;Schiestl, Florian P.
通讯作者：
Schiestl, Florian P.
影响因子：
1.4
作者：
GALEN, C;KEVAN, PG
通讯作者：
KEVAN, PG
影响因子：
11.6
作者：
Dudareva, N;Martin, D;Bohlmann, J
通讯作者：
Bohlmann, J