Adaptation mechanisms of grape varieties in unstable climatic conditions of the autumn-winter period

Despite the increase in the average annual temperature observed in recent decades, the urgency of the problem of cold resistance of plants not only does not decrease, but also increases. The purpose of the work is to identify the mechanisms of adaptation of grape varieties of various origins to low temperatures in the autumn-winter period in terms of physiological and biochemical indicators, to identify varieties with a high adaptive potential for cultivation in the Anapo-Taman zone of the Krasnodar Region. Objects of the study: interspecific hybrids of grapes of various ecological and geographical origin: Crystal (control) - Euro-Amur-American; Krasnostop AZOS, Dostoyny - Euro-American; Vostorg - Amur-American; Zarif - Eastern European; Aligote - Western European origin. The implementation of the mechanisms of resistance of grapes to low temperatures was achieved by reducing the water content of tissues, increasing the proportion of bound water, the content of ascorbic acid, and changing the activity of peroxidase. Varieties Crystal, Krasnostop AZOS, Vostorg were distinguished by an increased ratio of bound and free water - 3.8-6.8; maximum accumulation of ascorbic acid (19.3-21.3 μg/g fresh weight), reduced peroxidase activity in comparison with other studied varieties. Varieties such as Crystal, Krasnostop AZOS, Vostorg proved to be more adaptive in comparison with other studied varieties and are recommended for the usage in the breeding process.

Formation of adaptive responses of grapes to the action of abiotic stressors of the winter period

The purpose of this work is to study the formation of adaptive reactions of grapes to the action of stressors of the winter period, by physiological and biochemical parameters, to identify varieties that have increased adaptive abilities for use in breeding. Objects of research are grape varieties of different origins: Kristall (control), Dostoynyi, Krasnostop AZOS, Vostorg, Aligote, Zarif. It was revealed that the increased resistance to winter stress conditions in the varieties Kristall, Dostoyny is achieved by a decrease in the water content of the buds by 9.09-10.40 %. In the varieties Vostorg, Dostoyny, Krasnostop AZOS adaptive resistance is achieved by increasing the starch content in the tissues of the shoots by 2.81-5.50 times in the pre-winter period. In varieties Krasnostop AZOS, Vostorg an important contribution to the formation of adaptive processes was made by water-soluble sugars, the content of which increased 2.82 and 2.89 times as a result of starch hydrolysis. An increase in the activity of peroxidase (2.49-2.75 times) indicated the instability of varieties Zarif, Aligote. Varieties Vostorg, Dostoynyi, Krasnostop AZOS have increased adaptive abilities in comparison with other studied varieties and are recommended for use in the breeding process.

Adaptive resistance of apple trees in the unstable climate of southern Russia

The purpose of these studies is to assess the adaptive resistance of the apple tree to winter stresses in terms of physiological and biochemical parameters, to identify the most resistant varieties for cultivation in the Krasnodar region. Objects of research are apple varieties of various origins: Orfey, Idared, Ligol, Prikubanskoe. It was found that the cryoprotective function of water-soluble sugars was maximally manifested in the varieties Orfey and Ligol, their content increased by 2.56 and 2.7 times, respectively. Soluble proteins made the greatest contribution to the formation of a protective response in Orfey and Prikubanskoye varieties in January, their content increased 1.8 and 1.9 times, respectively, compared to December. The protective function of anthocyanins was maximally manifested in December in the Orfey variety, in the bark of which their content increased by 5.6 times. Physiological and biochemical adaptation of apple varieties to low negative temperatures of the winter period is achieved by increasing the content of water-soluble sugars, proteins in anthocyanins in the bark and buds. According to the obtained data, the apple varieties Orfey and Prikubanskoye showed themselves to be more adaptive in comparison with other studied varieties and are recommended for cultivation in the Krasnodar region.

Studying of the resistance to winter stresses of grapevine varieties of different ecological and geographical origin

In terms of climate change researches about adaptation mechanism of perennial crop plant to summer and winter stresses are actual. Physiological-biochemical assessment of grapevine varieties allows to clarify the mechanisms of protective and adaptive reaction on stresses and identify perspective genotypes for cultivation in stressful terms. Ecological and geographical origin are important in this case. Winterhardiness of following grapevine varieties: ‘Kristal’, ‘Aligote’, ‘Dostoyniy’ ‘Krasnostop AZOS’, ‘Zarif’ and ‘Vostorg’, are studied in conditions of Anapa-Taman region of the Russian Federation. At the beginning of winter reduced water content of vine tissue are noted for ‘Kristal’, ‘Krasnostop AZOS’ and ‘Dostoyniy’ (41,4-45,3 %). Also, for this varieties are found elevated accumulation of sucrose (2 times more) which means high resistance to low temperature. Intensification of antioxidative protective system’s functioning in response on stress are discovered for varieties ‘Kristal’, ‘Krasnostop AZOS’, ‘Dostoyniy’ and ‘Vostorg’. High containing of anthocyanins and chalcones in varieties ‘Kristal’, ‘Dostoyniy’, ‘Krasnostop AZOS’ and ascorbic acid in varieties ‘Krasnostop AZOS’, ‘Dostoyniy’ are revealed. According to generalized assessment of physiological-biochemical research results in conditions of climate change in Anapa-Taman region of Russia more winterhardiness were varieties ‘Krasnostop AZOS’, ‘Dostoyniy’, ‘Kristal’ than varieties ‘Aligote’, ‘Vostorg’, ‘Zarif’.

Use of physiological and biochemical indicators to identify apple varieties resistant to drought

As a result of global climate change in the arid regions of the world, a decrease in the adaptability of fruit crops to drought has been noted. This explains the interest of researchers in the issues of increasing the drought resistance of fruit crops in various ways, one of which is the creation of resistant varieties as a result of selection. The use of physiological and biochemical parameters in the breeding process as diagnostic criteria for drought resistance and the identification of highly adaptive varieties of fruit crops is relevant all over the world. The objects of study are apple varieties of various ecological and geographical origins: Idared, Erli Mac, Dayton (USA), Prikubanskoe, Rassvet, Fortuna (Russia). Physiological parameters: the relative water content, the total content of chlorophylls (a + b), carotenoids, ascorbic acid in the leaves of the studied apple varieties were determined during periods before drought and during drought. Differences in the response of varieties to the impact of drought were revealed. It was found that apple varieties of local selection Prikubanskoye, Fortuna and American variety Idared have a greater ability to adapt to changing environmental conditions in comparison with other studied varieties. The revealed adaptive features during drought (retention of a high relative water content, stability of the pigment system, a low ratio of the total chlorophyll to carotenoids, an increased content of ascorbic acid) make it possible to use them in breeding as donors of drought resistance traits. The data of physiological and biochemical studies, obtained in the unique natural and climatic conditions of the North Caucasus region of Russia, complement fundamental research on the physiological foundations of apple tree adaptation to drought.

Long-term trends in mortality and AIDS-defining events after combination ART initiation among children and adolescents with perinatal HIV infection in 17 middle- and high-income countries in Europe and Thailand: A cohort study

BACKGROUND

Published estimates of mortality and progression to AIDS as children with HIV approach adulthood are limited. We describe rates and risk factors for death and AIDS-defining events in children and adolescents after initiation of combination antiretroviral therapy (cART) in 17 middle- and high-income countries, including some in Western and Central Europe (W&CE), Eastern Europe (Russia and Ukraine), and Thailand.

METHODS AND FINDINGS

Children with perinatal HIV aged <18 years initiating cART were followed until their 21st birthday, transfer to adult care, death, loss to follow-up, or last visit up until 31 December 2013. Rates of death and first AIDS-defining events were calculated. Baseline and time-updated risk factors for early/late (≤/>6 months of cART) death and progression to AIDS were assessed. Of 3,526 children included, 32% were from the United Kingdom or Ireland, 30% from elsewhere in W&CE, 18% from Russia or Ukraine, and 20% from Thailand. At cART initiation, median age was 5.2 (IQR 1.4-9.3) years; 35% of children aged <5 years had a CD4 lymphocyte percentage <15% in 1997-2003, which fell to 15% of children in 2011 onwards (p < 0.001). Similarly, 53% and 18% of children ≥5 years had a CD4 count <200 cells/mm3 in 1997-2003 and in 2011 onwards, respectively (p < 0.001). Median follow-up was 5.6 (2.9-8.7) years. Of 94 deaths and 237 first AIDS-defining events, 43 (46%) and 100 (42%) were within 6 months of initiating cART, respectively. Multivariable predictors of early death were: being in the first year of life; residence in Russia, Ukraine, or Thailand; AIDS at cART start; initiating cART on a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen; severe immune suppression; and low BMI-for-age z-score. Current severe immune suppression, low current BMI-for-age z-score, and current viral load >400 c/mL predicted late death. Predictors of early and late progression to AIDS were similar. Study limitations include incomplete recording of US Centers for Disease Control (CDC) disease stage B events and serious adverse events in some countries; events that were distributed over a long time period, and that we lacked power to analyse trends in patterns and causes of death over time.

CONCLUSIONS

In our study, 3,526 children and adolescents with perinatal HIV infection initiated antiretroviral therapy (ART) in countries in Europe and Thailand. We observed that over 40% of deaths occurred ≤6 months after cART initiation. Greater early mortality risk in infants, as compared to older children, and in Russia, Ukraine, or Thailand as compared to W&CE, raises concern. Current severe immune suppression, being underweight, and unsuppressed viral load were associated with a higher risk of death at >6 months after initiation of cART.