La Peyre Jerome F, Casas Sandra M, Richards Mackenzie, Xu Wei, Xue Qinggang
School of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA.
Dis Aquat Organ. 2019 Feb 28;133(2):127-139. doi: 10.3354/dao03344.
Recent findings have suggested that eastern oyster plasma possesses inhibitors of the protease subtilisin, which play a role in the host defense against Perkinsus marinus, a protist parasite causing dermo. A study was conducted to determine whether plasma subtilisin inhibitory activity (PSIA) could be used as a selective marker in breeding programs for dermo resistance. Eastern oysters Crassostrea virginica from 2 wild Louisiana populations shown to differ in dermo resistance were collected and their PSIA was measured. Three groups of oysters were established to spawn from each population. One group was composed of randomly sampled oysters (i.e. unselected) and the other 2 groups were composed of oysters with the highest or lowest PSIA. After spawning, progenies were deployed in October 2014 in a dermo endemic area and sampled quarterly for 2 yr to measure their mortality, growth, P. marinus infection intensity, condition index, PSIA, and the gene expression of 3 subtilisin inhibitors (cvSI-1, cvSI-2, and cvSI-3). Oyster cumulative mortalities of the progenies of all groups increased both years from April to October, concomitant with increasing P. marinus infection intensities. Mortalities and P. marinus infection intensities differed markedly between the 2 populations, but differences between the unselected and selected groups of each population were limited. Measurements of PSIA and cvSI-1, cvSI-2, and cvSI-3 gene expressions between the progenies of all groups showed few differences. CvSI-1 gene expression in surviving oysters of the most susceptible population was increased at the end of the study, adding additional support to the potential role of cvSI-1 defense against P. marinus.
最近的研究结果表明，东部牡蛎血浆中含有枯草杆菌蛋白酶抑制剂，这些抑制剂在宿主抵御海洋派琴虫（一种导致牡蛎皮肤溃疡病的原生动物寄生虫）的防御中发挥作用。开展了一项研究，以确定血浆枯草杆菌蛋白酶抑制活性（PSIA）是否可作为抗皮肤溃疡病育种计划中的一个选择性标记。采集了来自路易斯安那州两个野生种群、对皮肤溃疡病抗性不同的弗吉尼亚牡蛎，并测定了它们的PSIA。从每个种群中建立了三组牡蛎用于产卵。一组由随机抽样的牡蛎组成（即未选择），另外两组由PSIA最高或最低的牡蛎组成。产卵后，于2014年10月将后代放养在一个皮肤溃疡病流行区，并在两年内每季度取样，以测量它们的死亡率、生长情况、海洋派琴虫感染强度、状况指数、PSIA以及三种枯草杆菌蛋白酶抑制剂（cvSI - 1、cvSI - 2和cvSI - 3）的基因表达。所有组后代的牡蛎累积死亡率在这两年的4月至10月均有所增加，同时海洋派琴虫感染强度也在增加。两个种群之间的死亡率和海洋派琴虫感染强度差异显著，但每个种群中未选择组和选择组之间的差异有限。所有组后代之间的PSIA以及cvSI - 1、cvSI - 2和cvSI - 3基因表达测量结果显示差异不大。在研究结束时，最易感种群中存活牡蛎的cvSI - 1基因表达增加，这进一步支持了cvSI - 1在抵御海洋派琴虫方面的潜在作用。
