Co-Variation of Chemical and Mechanical Defenses in Lima Bean (Phaseolus lunatus L.)
Co-Variation of Chemical and Mechanical Defenses in Lima Bean (Phaseolus lunatus L.)
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DOI：
10.1007/s10886-013-0255-6
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发表时间：
2013-03-01
影响因子：
2.3
通讯作者：
Kautz, Stefanie
中科院分区：
文献类型：
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作者：
Ballhorn, Daniel J.;Godschalx, Adrienne L.;Kautz, Stefanie
植物通常同时表达多种化学和机械防御。人们对这些防御的相互作用仍然知之甚少，因为预测范围从分配权衡等负面关联到形成协同防御综合症的正相关性。令人惊讶的是，很少有经验证据存在的多种植物防御的共同变化。本研究对不同基因型的利马豆（Phaseolus lunatus L.）表达两种直接化学防御[生氰潜力（组成型），多酚氧化酶活性（诱导型）]，两种间接化学防御[挥发物（VOC）和花外花蜜（EFN;两者均可诱导）]和组成型机械防御（钩形毛状体）。虽然毛状体的发生与氰生成呈正相关，但这些性状与多酚氧化酶活性、VOCs释放和EFN分泌呈权衡关系。钩状毛状体大量存在于14个基因型调查的四个，只发现在一个单系组的AFLP为基础的树，从而表明一个单一的进化起源的物种。我们的研究结果表明，不同的利马豆基因型表达两种防御系统之一：1）高组成防御通过氰和毛状体或2）高诱导防御通过挥发性有机化合物，EFN，和PPO活性。
Plants usually express multiple chemical and mechanical defenses simultaneously. The interplay of these defenses is still poorly understood, as predictions range from negative associations such as allocation tradeoffs to positive correlations forming synergistic defense syndromes. Surprisingly, little empirical evidence exists on the co-variation of multiple plant defenses. In the present study, we analyzed different genotypes of lima bean (Phaseolus lunatus L.) for the expression of two direct chemical defenses [cyanogenic potential (constitutive), polyphenol oxidase activity (inducible)], two indirect chemical defenses [volatiles (VOCs) and extrafloral nectar (EFN; both inducible)] and a constitutive mechanical defense (hook-shaped trichomes). While the occurrence of trichomes was positively correlated with cyanogenesis, these traits showed a tradeoff with polyphenol oxidase activity, release of VOCs, and secretion of EFN. Hook-shaped trichomes were abundantly present in four of 14 genotypes investigated, and were found only in one monophyletic group of an AFLP-based tree, thus indicating a single evolutionary origin within the species. Our findings show that different lima bean genotypes express either one of two defense systems: 1) high constitutive defense via cyanogenesis and trichomes or 2) high inducible defense via VOCs, EFN, and PPO activity.