The dinoflagellate Karenia brevis, blooms annually in the Gulf of Mexico, producing a suite of neurotoxins known as the brevetoxins. The cellular toxin content of K. brevis, however, is highly variable between or even within strains. Herein, we investigate physiological differences between high (KbHT) and low (KbLT) toxin producing cultures both derived from the Wilson strain, related to energy-dependent quenching (qE) by photosystem II, and reduced thiol content of the proteome. We demonstrate that gene and protein expression of the xanthophyll cycle enzyme diadinoxanthin de-epoxidase (Dde) and monogalactosyldiacylglycerol (MGDG) synthase are not significantly different in the two cultures. Using redox proteomics, we report a significantly higher reduced cysteine content in the low toxin proteome, including plastid localized thioredoxin reductase (Trx) which can result in inactivation of Dde and activation of MGDG synthase. We also report significant differences in the lipidomes of KbHT and KbLT with respect to MGDG, which facilitates the xanthophyll cycle.

甲藻Karenia brevis每年在墨西哥湾开花，产生一系列称为短毒素的神经毒素。然而， K. brevis的细胞毒素含量在菌株之间甚至菌株内变化很大。在此，我们研究了高 ( Kb HT) 和低 ( KbLT) 产生毒素的培养物均源自 Wilson 菌株，与光系统 II 的能量依赖性淬灭 (qE) 相关，并降低了蛋白质组的硫醇含量。我们证明叶黄素循环酶 diadinoxanthin 脱环氧酶 (Dde) 和单半乳糖基二酰基甘油 (MGDG) 合酶的基因和蛋白质表达在两种培养物中没有显着差异。使用氧化还原蛋白质组学，我们报告了低毒素蛋白质组中半胱氨酸含量显着降低，包括质体局部硫氧还蛋白还原酶 (Trx)，它可导致 Dde 失活和 MGDG 合酶激活。我们还报告了Kb HT 和Kb LT的脂质组相对于 MGDG 的显着差异，这促进了叶黄素循环。