Lackus Nathalie D, Müller Andrea, Kröber Tabea D U, Reichelt Michael, Schmidt Axel, Nakamura Yoko, Paetz Christian, Luck Katrin, Lindroth Richard L, Constabel C Peter, Unsicker Sybille B, Gershenzon Jonathan, Köllner Tobias G
Department of Biochemistry, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
Nuclear Magnetic Resonance Department, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
Plant Physiol. 2020 May;183(1):137-151. doi: 10.1104/pp.19.01447. Epub 2020 Feb 25.
Salicinoids form a specific class of phenolic glycosides characteristic of the Salicaceae. Although salicinoids accumulate in large amounts and have been shown to be involved in plant defense, their biosynthesis is unclear. We identified two sulfated salicinoids, salicin-7-sulfate and salirepin-7-sulfate, in black cottonwood (). Both compounds accumulated in high amounts in above-ground tissues including leaves, petioles, and stems, but were also found at lower concentrations in roots. A survey of salicin-7-sulfate and salirepin-7-sulfate in a subset of poplar ( sp.) and willow ( sp.) species revealed a broader distribution within the Salicaceae. To elucidate the formation of these compounds, we studied the sulfotransferase () gene family in (). One of the identified genes, , was shown to encode an enzyme able to convert salicin and salirepin into salicin-7-sulfate and salirepin-7-sulfate, respectively. The expression of in different organs of matched the accumulation of sulfated salicinoids in planta. Moreover, RNA interference-mediated knockdown of in gray poplar ( × ) resulted in decreased levels of sulfated salicinoids in comparison to wild-type plants, indicating that SOT1 is responsible for their formation in planta. The presence of a nonfunctional allele in black poplar () was shown to correlate with the absence of salicin-7-sulfate and salirepin-7-sulfate in this species. Food choice experiments with leaves from wild-type and knockdown trees suggest that sulfated salicinoids do not affect the feeding preference of the generalist caterpillar A potential role of the sulfated salicinoids in sulfur storage and homeostasis is discussed.
水杨苷类化合物构成了杨柳科特有的一类特定的酚苷。尽管水杨苷类化合物大量积累且已被证明参与植物防御，但其生物合成尚不清楚。我们在黑杨（）中鉴定出两种硫酸化水杨苷类化合物，水杨苷 - 7 - 硫酸盐和水杨素 - 7 - 硫酸盐。这两种化合物在包括叶片、叶柄和茎在内的地上组织中大量积累，但在根中也以较低浓度被发现。对一部分杨树（属）和柳树（属）物种中的水杨苷 - 7 - 硫酸盐和水杨素 - 7 - 硫酸盐进行的调查揭示了它们在杨柳科中更广泛的分布。为了阐明这些化合物的形成过程，我们研究了黑杨（）中的磺基转移酶（）基因家族。其中一个鉴定出的基因，，被证明编码一种能够分别将水杨苷和水杨素转化为水杨苷 - 7 - 硫酸盐和水杨素 - 7 - 硫酸盐的酶。在黑杨不同器官中的表达与植物中硫酸化水杨苷类化合物的积累情况相匹配。此外，与野生型植物相比，在灰杨（×）中通过RNA干扰介导的对的敲低导致硫酸化水杨苷类化合物水平降低，这表明SOT1负责它们在植物中的形成。在黑杨（）中存在一个无功能的等位基因与该物种中水杨苷 - 7 - 硫酸盐和水杨素 - 7 - 硫酸盐的缺失相关。用野生型和敲低植株的叶片进行的食物选择实验表明，硫酸化水杨苷类化合物不会影响多食性毛虫的取食偏好。本文还讨论了硫酸化水杨苷类化合物在硫储存和体内平衡中的潜在作用。
