Vadim V. Fedyaev

It has become widespread knowledge that many signaling molecules are common to organisms of different groups. This is likely to be valid for such important metabolism regulators as iodothyronines. A number of studies have confirmed the presence of thyroid hormone activity in compounds of plant origin. However, these studies do not explain whether the compounds under consideration are iodine derivatives of thyronine, similar to animal and human thyroid hormones, or whether they are mimetics of thyroid hormones. In this work, we aim to verify the presence of iodothyronine analogs with different degrees of iodization in plant tissues. We also aim to determine iodine concentrations in plant tissue lysates and to compare them with the theoretically calculated values in order to test the assumption about the identity of their structure to human thyroid hormones. It was shown that tetraiodothyronine (T4) and triiodothyronine (T3) analogs are simultaneously present in potato tubers and wheat leaves. In potato tubers at dormancy, the concentration of T4 was 118 ± 16 nmol/L (n = 15), while the concentration of T3 in the same samples was 4.01 ± 0.96 nmol/L. T4 and T3 concentrations in wheat leaf lysates were 60.24 ± 79 and 6.76 nmol/L (n = 15), respectively. According to the results of inductively coupled plasma mass spectrometry, the studied samples contain iodine in the amounts consistent with the assumption about the presence of tetraiodinated tyronine derivatives.

Brassinosteroids (BRs) represent a group of plant signaling molecules with a steroidal skeleton that play an essential role in plant adaptation to different environmental stresses, including drought. In this work, the effect of pretreatment with 0.4 µM 24-epibrassinolide (EBR) on the oxidant/antioxidant system in 4-day-old wheat seedlings (Triticum aestivum L.) was studied under moderate drought stress simulated by 12% polyethylene glycol 6000 (PEG). It was revealed that EBR-pretreatment had a protective effect on wheat plants as evidenced by the maintenance of their growth rate, as well as the reduction in lipid peroxidation and electrolyte leakage from plant tissues under drought conditions. This effect was likely due to the ability of EBR to reduce the stress-induced accumulation of reactive oxygen species (ROS) and modulate the activity of antioxidant enzymes. Meanwhile, EBR pretreatment enhanced proline accumulation and increased the barrier properties of the cell walls in seedlings by accelerating the lignin deposition. Moreover, the ability of EBR to prevent a drought-caused increase in the intensity of the total dark respiration and the capacity of alternative respiration contributes significantly to the antistress action of this hormone.

The phytoremediation of soil contaminated with petroleum depends on the association of plants with rhizosphere bacteria capable of promoting plant growth and destroying petroleum hydrocarbonates. In the present work, we studied the effects of “Lenoil” biological product containing bacteria Pseudomonas turukhanskensis IB 1.1, capable of destroying petroleum hydrocarbons on Secale cereale L plants, which previously proved to be resistant to the weak oil pollution of gray forest soil and to the composition of microorganisms in their rhizosphere. The composition of microorganisms in the rhizosphere of rye roots was studied, morphometric parameters of shoots and roots of rye plants were estimated, and hormone concentration was immunoassayed under conditions of 4% petroleum pollution of the soil. Addition of petroleum to the soil increased the content of oligonitrophilic (by 24%) and hydrocarbon-oxidizing (by 33%) microorganisms; however, the content of cellulolytic (by 12.5 times) microorganisms in the rhizosphere decreased. The use of Lenoil led to a further increase in the number of cellulolytic (by 5.6 times) and hydrocarbon-oxidizing (by 3.8 times) microorganisms and a decrease in the number of oligonitrophilic (by 22.7%) microorganisms in the rhizosphere. Under petroleum pollution, the content of auxins (IAA), zeatin riboside, zeatin nucleotide, and zeatin decreased, while the content of abscisic acid (ABA) increased in the shoots of rye plants. Lenoil treatment led to an eight-fold increase in the IAA content in the roots and a decrease in the ABA content in the aerial part and in the roots. It was shown for the first time that the treatment of petroleum-contaminated soil with “Lenoil” increased root mass due to the development of lateral roots, concurrent with high root IAA content. Petroleum pollution increased the deposition of lignin and suberin in the roots, which strengthened the apoplastic barrier and, thus, reduced the infiltration of toxic components. The deposition of suberin and lignin decreased under ”Lenoil” treatment, indicating a decrease in the concentration of toxic petroleum components in the soil degraded by the bacteria. Thus, the biological preparation reduced the growth-inhibiting effect of petroleum on rye plants by increasing the content of growth-stimulating phytohormones (IAA and cytokinins) and reducing the content of ABA, justifying the importance of further study of relevant hormones for the improvement of phytoremediation.

Article 5122. Пензенский государственный университет

Changes in root elongation are important for the acquisition of mineral nutrients by plants. Plant hormones, cytokinins, and abscisic acid (ABA) and their interaction are important for the control of root elongation under changes in the availability of ions. However, their role in growth responses to supra-optimal concentrations of nitrates and phosphates has not been sufficiently studied and was addressed in the present research. Effects of supra-optimal concentrations of these ions on root elongation and distribution of cytokinins between roots and shoots were studied in ABA-deficient barley mutant Az34 and its parental variety, Steptoe. Cytokinin concentration in the cells of the growing root tips was analyzed with the help of an immunohistochemical technique. Increased concentrations of nitrates and phosphates led to the accumulation of ABA and cytokinins in the root tips, accompanied by a decline in shoot cytokinin content and inhibition of root elongation in Steptoe. Neither of the effects were detected in Az34, suggesting the importance of the ability of plants to accumulate ABA for the control of these responses. Since cytokinins are known to inhibit root elongation, the effect of supra-optimal concentration of nitrates and phosphates on root growth is likely to be due to the accumulation of cytokinins brought about by ABA-induced inhibition of cytokinin transport from roots to shoots.

Общеизвестно метаболическое значение йодтиронинов в организме человека и животных. Для растений подобные соединения не описаны, однако, известны эффекты лекарственных растений на функцию щитовидной железы, что предполагает возможность присутствия соединений, аналогичных тиреоидным гормонам в клетках растений. Цель работы - выявление в клетках высших растений биологически наиболее активного представителя йодтиронинов - 3,5,3’-трийодтиронина. Методом иммуноферментного анализа показано, что в тканях корня и стебля проростков фасоли присутствует соединение, взаимодействующее с поликлональной сывороткой к 3,5,3’-трийодтиронину. Установлено, что в клетке выявленное соединение распределено неравномерно: в ядрах клеток его концентрация в 7-10 раз выше, чем в цитоплазме. Наряду с растениями фасоли исследованы 8 случайно выбранных растений, принадлежащих как к двудольным, так и однодольным растениям. Во всех исследованных растениях методом иммуноферментного анализа определено присутствие аналога 3,5,3’-трийодтиронина. Добавление экзогенного йодтиронина - тироксина (3,5,3’,5’-тетрайодтирони-на) при предпосевной обработке семян пшеницы достоверно повысило их всхожесть и привело к значимому увеличению соотношения массы побега к массе корня пятисуточных растений пшеницы при времени замачивания 6 и 12 ч. Вследствие обработки семян пшеницы тироксином в ядрах клеток стебля и корня пятидневных растений пшеницы произошло достоверное снижение концентрации выявленного соединения. Накопление в ядрах клеток и выявленные физиологические эффекты экзогенного 3,5,3’,5’-тетрайодтиронина позволяют предположить, что в клетках высших растений данное соединение принимает участие в регуляции активности генов подобно тому, как это имеет место в клетках животных.

Article 9321. Пензенский государственный университет

A Pseudomonas sp. 102 strain, which is highly resistant to toxic effects of cadmium and has plant growth-promoting activity, can significantly increase growth parameters and biomass of tomato plants, including those observed under toxic effects of cadmium. The greatest positive effect was observed in plants transformed with the bacterial adhesin gene rapA1, the product of which is important for colonization of plant roots by bacteria. It was also shown that shoots of transgenic tomato plants accumulated the greatest amount of cadmium during inoculation with Pseudomonas sp. 102. The ability to extract high concentrations of cadmium and accumulate a large biomass under stress opens up prospects for the further use of associative interactions between tomato and Pseudomonas for phytoremediation. phytoremediation, cadmium, tomato, Pseudomonas, inoculation, agglutinins, This study was carried out using the equipment of the Biomika Centre for Collective Use of the Institute of Biochemistry and Genetics (Ufa Federal Research Centre, Russian Academy of Sciences) as part of the government task (project no. AAAA-A16-1160203500284). This study was supported by the Russian Foundation for Basic Research (project nos. 18-34-20004 and 18-34-00033) and 18-344-0033 mol_a_ved and 34-00033 mol_a).