Role of antioxidants in the protection against the combined effect of Cd, Zn, and Ni in wheat

The effect of the combined treatment with Cd, Zn, and Ni on the accumulation of these metals, growth, and contents of antioxidants in wheat roots is studied. The metals were added in two concentrations to the nutrient solution for seedlings, and the higher one had a stronger effect on the studied parameters. The heavy-metal tolerances of 8 wheat varieties are compared in order to select the most tolerant (Kuial’nik) and most sensitive one (Sonechko) for biochemical studies. The heavy-metal uptake and, subsequently, the lipid peroxidation are smaller in the tolerant genotype, than in the sensitive one. The higher glutathione concentration in the tolerant genotype under control conditions could contribute to the improved heavy-metal tolerance. The metal-induced decrease in the glutathione content can be an indicator of the increased phytochelatin synthesis. The great tolerance of Kuial’nik can be explained by its decreased heavy-metal uptake and the greater glutathione-based antioxidant capacity.Наведено результати вивчення комбiнованого впливу Cd, Zn i Ni на накопичення цих металiв, рiст i вмiст антиоксидантiв у коренях пшеницi. Метали додавали в двох концентрацiях у поживне середовище проросткiв, вища концентрацiя справляла сильнiший вплив на дослiджуванi показники. Вивчали толерантнiсть 8 сортiв пшеницi до важких металiв з метою обрати найбiльш толерантний (Куяльник) i найбiльш чутливий (Сонечко) для бiохiмiчних дослiджень. Поглинання важких металiв та iнтенсивнiсть пероксидного окиснення лiпiдiв були меншими у толерантного генотипу порiвняно з чутливим. Висока концентрацiя глутатiону у толерантного генотипу за контрольних умов може бути пов’язана з пiдвищеною толерантнiстю до важких металiв. Металiндуковане зменшення вмiсту глутатiону може бути iндикатором пiдвищеного синтезу фiтохелатинiв. Бiльшу толерантнiсть сорту Куяльник можна пояснити зниженим поглинанням важких металiв i бiльш iнтенсивним функцiонуванням глутатiонзалежної ланки антиоксидантного захисту.Приведены результаты изучения комбинированного воздействия Cd, Zn и Ni на накопление этих металлов, рост и содержание антиоксидантов в корнях пшеницы. Металлы добавляли в двух концентрациях в питательную среду проростков, высокая концентрация оказывала более сильное влияние на исследуемые показатели. Изучали толерантность 8 сортов пшеницы к тяжелым металлам с целью выбрать наиболее толерантный (Куяльник) и наиболее чувствительный (Солнышко) для биохимических исследований. Поглощение тяжелых металлов и интенсивность пероксидного окисления липидов были меньше у толерантного генотипа по сравнению с чувствительным. Высокая концентрация глутатиона у толерантного генотипа в контрольных условиях может быть связана с повышенной толерантностью к тяжелым металлам. Индуцированное металлами снижение содержания глутатиона может быть индикатором повышенного синтеза фитохелатинов. Большую толерантность сорта Куяльник можно объяснить пониженным поглощением тяжелых металлов и более интенсивным функционированием глутатионзависимого звена антиоксидантной защиты

Mapping of Genes Involved in Glutathione, Carbohydrate and COR14b Cold Induced Protein Accumulation during Cold Hardening in Wheat

Using some of the chromosome substitution lines developed from the crosses of the donor Cheyenne to Chinese Spring we showed that the accumulation of water soluble carbohydrates during different stages of hardening was time dependent. Moreover there was a significant correlation between the rate of carbohydrate accumulation and the frost tolerance. The expression and regulation of a wheat gene homologous to the barley cold regulated cor14b gene was compared in frost sensitive and frost tolerant wheat genotypes at different temperatures. Studies made with chromosome substitution lines showed that the threshold induction temperature polymorphism of the cor14b wheat homologous gene was controlled by loci located on chromosome 5A of wheat, while cor14b gene was mapped, in Triticum monococcum, onto the long arm of chromosome 2Am. Our study on the effect of cold hardening on glutathione (GSH) metabolism showed that chromosome 5A of wheat has an influence on the GSH accumulation and on the ratio of reduced and oxidised glutathione as part of a complex regulatory function during cold hardening. In addition, the level of increase in GSH content during hardening may indicate the degree of the frost tolerance of wheat

Interaction of Temperature and Light in the Development of Freezing Tolerance in Plants

Abstract Freezing tolerance is the result of a wide range of physical and biochemical processes, such as the induction of antifreeze proteins, changes in membrane composition, the accumulation of osmoprotectants, and changes in the redox status, which allow plants to function at low temperatures. Even in frost-tolerant species, a certain period of growth at low but nonfreezing temperatures, known as frost or cold hardening, is required for the development of a high level of frost hardiness. It has long been known that frost hardening at low temperature under low light intensity is much less effective than under normal light conditions; it has also been shown that elevated light intensity at normal temperatures may partly replace the cold-hardening period. Earlier results indicated that cold acclimation reflects a response to a chloroplastic redox signal while the effects of excitation pressure extend beyond photosynthetic acclimation, influencing plant morphology and the expression of certain nuclear genes involved in cold acclimation. Recent results have shown that not only are parameters closely linked to the photosynthetic electron transport processes affected by light during hardening at low temperature, but light may also have an influence on the expression level of several other cold-related genes; several cold-acclimation processes can function efficiently only in the presence of light. The present review provides an overview of mechanisms that may explain how light improves the freezing tolerance of plants during the cold-hardening period

Revising mtDNA haplotypes of the ancient Hungarian conquerors with next generation sequencing

As part of the effort to create a high resolution representative sequence database of the medieval Hungarian conquerors we have resequenced the entire mtDNA genome of 24 published ancient samples with Next Generation Sequencing, whose haplotypes had been previously determined with traditional PCR based methods. We show that PCR based methods are prone to erroneous haplotype or haplogroup determination due to ambiguous sequence reads, and many of the resequenced samples had been classified inaccurately. The SNaPshot method applied with published ancient DNA authenticity criteria is the most straightforward and cheapest PCR based approach for testing a large number of coding region SNP-s, which greatly facilitates correct haplogroup determination

Transcriptional responses of winter barley to cold indicate nucleosome remodelling as a specific feature of crown tissues

We report a series of microarray-based comparisons of gene expression in the leaf and crown of the winter barley cultivar Luxor, following the exposure of young plants to various periods of low (above and below zero) temperatures. A transcriptomic analysis identified genes which were either expressed in both the leaf and crown, or specifically in one or the other. Among the former were genes responsible for calcium and abscisic acid signalling, polyamine synthesis, late embryogenesis abundant proteins and dehydrins. In the crown, the key organ for cereal overwintering, cold treatment induced transient changes in the transcription of nucleosome assembly genes, and especially H2A and HTA11, which have been implicated in cold sensing in Arabidopsis thaliana. In the leaf, various heat-shock proteins were induced. Differences in expression pattern between the crown and leaf were frequent for genes involved in certain pathways responsible for osmolyte production (sucrose and starch, raffinose, γ-aminobutyric acid metabolism), sugar signalling (trehalose metabolism) and secondary metabolism (lignin synthesis). The action of proteins with antifreeze activity, which were markedly induced during hardening, was demonstrated by a depression in the ice nucleation temperature