Horgan Finbarr G, Srinivasan Thanga Suja, Crisol-Martínez Eduardo, Almazan Maria Liberty P, Ramal Angelee Fame, Oliva Ricardo, Quibod Ian L, Bernal Carmencita C
EcoLaVerna Integral Restoration Ecology Kildinan Ireland.
University of Technology Sydney Sydney NSW Australia.
Ecol Evol. 2019 Oct 4;9(20):11911-11929. doi: 10.1002/ece3.5699. eCollection 2019 Oct.
The microbiomes of phloem-feeding insects include functional bacteria and yeasts essential for herbivore survival and development. Changes in microbiome composition are implicated in virulence adaptation by herbivores to host plant species or host populations (including crop varieties). We examined patterns in adaptation by the green leafhopper, , to near-isogenic rice lines (NILs) with one or two resistance genes and the recurrent parent T65, without resistance genes. Only the line with two resistance genes was effective in reducing leafhopper fitness. After 20 generations on the resistant line, selected leafhoppers attained similar survival, weight gain, and egg laying to leafhoppers that were continually reared on the susceptible recurrent parent, indicating that they had adapted to the resistant host. By sequencing the 16s rRNA gene, we described the microbiome of leafhoppers from colonies associated with five collection sites, and continually reared or switched between NILs. The microbiomes included 69-119 OTUs of which 44 occurred in ≥90% of samples. Of these, 14 OTUs were assigned to the obligate symbiont clade. After 20 generations of selection, collection site had a greater effect than host plant on microbiome composition. Six bacteria genera, including , were associated with leafhopper virulence. However, there was significant within-treatment, site-related variability in the prevalence of these taxa such that the mechanisms underlying their association with virulence remain to be determined. Our results imply that these taxa are associated with leafhopper nutrition. Ours is the first study to describe microbiome diversity and composition in rice leafhoppers. We discuss our results in light of the multiple functions of herbivore microbiomes during virulence adaptation in insect herbivores.
取食韧皮部昆虫的微生物群包括对食草动物生存和发育至关重要的功能性细菌和酵母。微生物群组成的变化与食草动物对寄主植物物种或寄主种群（包括作物品种）的毒力适应有关。我们研究了绿叶蝉对具有一个或两个抗性基因的近等基因水稻品系（NILs）以及没有抗性基因的轮回亲本T65的适应模式。只有具有两个抗性基因的品系能有效降低叶蝉的适合度。在抗性品系上饲养20代后，选择的叶蝉在存活率、体重增加和产卵方面与在易感轮回亲本上持续饲养的叶蝉相似，这表明它们已经适应了抗性寄主。通过对16s rRNA基因进行测序，我们描述了来自与五个采集地点相关的菌落、在NILs上持续饲养或在NILs之间转换的叶蝉的微生物群。这些微生物群包括69 - 119个操作分类单元（OTUs），其中44个出现在≥90%的样本中。其中，14个OTUs被归入专性共生菌分支。经过20代选择后，采集地点对微生物群组成的影响大于寄主植物。包括在内的六个细菌属与叶蝉毒力相关。然而，这些分类群的流行率在处理内存在显著的地点相关变异性，因此它们与毒力相关的潜在机制仍有待确定。我们的结果表明这些分类群与叶蝉营养有关。我们是第一项描述水稻叶蝉微生物群多样性和组成的研究。我们根据食草动物微生物群在昆虫食草动物毒力适应过程中的多种功能来讨论我们的结果。
