Gregorová Zuzana, Kováčik Jozef, Klejdus Bořivoj, Maglovski Marína, Kuna Roman, Hauptvogel Pavol, Matušíková Ildikó
Faculty of Natural Sciences, Department of Botany and Genetics, Constantine the Philosopher University , Nábrežie mládeže 91, 949 74 Nitra, Slovak Republic.
Institute of Plant Genetics and Biotechnology, Slovak Academy of Sciences , Akademická 2, P.O. Box 39A, 950 07 Nitra, Slovak Republic.
J Agric Food Chem. 2015 Sep 23;63(37):8125-33. doi: 10.1021/acs.jafc.5b02951. Epub 2015 Sep 14.
The impact of severe drought stress (13% soil moisture) on the physiological responses, metabolic profile, and pathogenesis-related (PR) proteins in wheat above- and below-ground biomass after 20 days of treatment was studied. Drought depleted growth, assimilation pigments, and majority of free amino acids in the shoots (but proline increased considerably, +160%). On the contrary, root growth parameters were elevated, and free amino acids did not decrease, indicating investment of metabolites into the growth of roots under water deficiency. Mineral nutrients were only slightly influenced. Profiling of pathogenesis-related (PR) proteins revealed that chitinases (EC 3.2.1.14) and glucanases (EC 3.2.1.39) were activated in wheat by drought. Individual isoforms and their activity were rather stimulated under drought, especially in shoots. The expression of selected genes is in agreement with enzymatic data and suggests an organ (tissue) specific- and opposing behavior of these two types of defense components in drought-stressed wheat. Metabolic analyses at the level of phenolics showed an increase in the free and bound fraction of phenolic acids almost exclusively in the shoots and flavonoid isoorientin increased considerably: protective action against oxidative stress and dehydration of the leaves seems to be the main reason for this finding. The role of PR proteins and phenolics in drought-stressed tissue is discussed.
研究了重度干旱胁迫（土壤湿度13%）处理20天后对小麦地上和地下生物量的生理反应、代谢谱及病程相关（PR）蛋白的影响。干旱使地上部分的生长、同化色素及大多数游离氨基酸减少（但脯氨酸大幅增加，+160%）。相反，根系生长参数升高，游离氨基酸并未减少，这表明在水分亏缺情况下代谢产物被用于根系生长。矿质营养仅受到轻微影响。病程相关（PR）蛋白分析表明，几丁质酶（EC 3.2.1.14）和葡聚糖酶（EC 3.2.1.39）在小麦中被干旱激活。个别同工型及其活性在干旱条件下尤其在地上部分受到更强刺激。所选基因的表达与酶学数据一致，表明这两种防御成分在干旱胁迫小麦中表现出器官（组织）特异性的相反行为。酚类物质水平的代谢分析表明，酚酸的游离和结合部分几乎仅在地上部分增加，黄酮类异荭草苷大幅增加：对叶片氧化应激和脱水的保护作用似乎是这一发现的主要原因。文中讨论了PR蛋白和酚类物质在干旱胁迫组织中的作用。
