Loss of heterosis and family‐dependent inbreeding depression in plant performance and resistance against multiple herbivores under drought stress
Loss of heterosis and family‐dependent inbreeding depression in plant performance and resistance against multiple herbivores under drought stress
复制标题
干旱胁迫下植物性能和对多种食草动物的抗性的杂种优势丧失和家族依赖性近交抑制
DOI：
10.1111/1365-2745.12327
复制
发表时间：
2014
影响因子：
5.5
通讯作者：
Roosa Leimu
中科院分区：
文献类型：
--
作者：
N. Prill;J. Bullock;N. M. Dam;Roosa Leimu
近交抑制（ID）、远交抑制（OD）和杂种优势在植物群体中可以同时发生。在环境胁迫下，遗传变异往往会增加，但种群间近交、远交以及干旱等环境胁迫对植物生产性能和草食抗性的综合影响尚不清楚。为了确定环境依赖和家族依赖的油菜ID、OD和杂种优势，我们对5个油菜居群进行了普通园艺试验。自交系、种群内近交系和种群间近交系植物暴露于干旱或环境水位。我们记录了来自不同摄食行业的特殊食草动物，即韧皮部摄食的bricoryne brassicae，咀嚼叶片的Psylliodes chrysocephalus和茎钻的Ceutorhynchus quadridens幼虫的丰度和危害。干旱胁迫对油菜的生长、抗草食性和抗性均有负面影响，而对生殖产量和植物次生代谢产物（紫穗槐素）的投入有积极影响。我们发现干旱胁迫导致植株高度和生殖产出投资的杂种优势丧失。就地上生物量而言，种群间近交系植物比种群内近交系植物对干旱胁迫更敏感。干旱和近交对与生长和繁殖产量相关的性状产生协同负向影响（环境依赖性近交抑制，EDID）。人群内不同家庭的ID和EDID程度差异较大。EDID的遗传变异可以缓冲生境破碎化相关的遗传压力和同时发生的环境压力的负面影响。为了充分捕捉压力下近交和种群间近交的效应，应考虑近交和种群间近交效应的不同空间尺度。合成。结果表明，干旱胁迫不仅影响近交抑制，而且影响杂种优势。这些发现揭示了人为环境变化和生境破碎化对植物及其与其他生物相互作用的遗传后果的综合影响。旨在恢复遗传退化种群并使个体在种群之间易位的保护方案应将环境压力视为一个风险因素。
Inbreeding depression (ID), outbreeding depression (OD) and heterosis can occur concurrently in plant populations. ID often increases under environmental stress, but the combined effects of inbreeding, outbreeding between populations and environmental stress, such as drought, on plant performance and herbivore resistance remain unclear. In order to determine environment‐dependent and family‐dependent ID, OD and heterosis, we conducted a common garden experiment with plants from five populations of Brassica nigra. Inbred, within‐population outbred and between‐population outbred plant families were exposed to drought or ambient water levels. We recorded the abundance and damage caused by specialist herbivores from contrasting feeding guilds, that is the phloem‐feeding Brevicoryne brassicae, the leaf‐chewing Psylliodes chrysocephalus and the stem‐boring Ceutorhynchus quadridens larvae. Drought stress had negative effects on growth, herbivore resistance and resistance against B. brassicae and positive effects on investments in reproductive output and plant secondary metabolites (sinigrin). We found drought stress‐induced loss of heterosis for plant height and investment in reproductive output. Between‐population outbred plants were more sensitive to drought stress in terms of above‐ground biomass compared to within‐population outbred plants. Drought and inbreeding synergistically negatively influenced traits related to growth and reproductive output (environment‐dependent inbreeding depression, EDID). There was high variation among families within populations in the degree of ID and EDID. Genetic variation in EDID could buffer the negative effects of genetic stress associated with habitat fragmentation and concurrent environmental stress. In order to capture fully the effects of both inbreeding and between‐population outbreeding under stress, the different spatial scales of the effects of inbreeding and between‐population outbreeding should be taken into account. Synthesis. Our results indicate that drought stress influences not only inbreeding depression (ID), but also heterosis. These findings shed new light on the combined effects of anthropogenic environmental change and the genetic consequences of habitat fragmentation on plants and their interactions with other organisms. Conservation programmes aiming to restore genetically degraded populations with the translocation of individuals between populations should consider environmental stress as a risk factor.