Common bean SNP alleles and candidate genes affecting photosynthesis under contrasting water regimes

Water deficit is a major worldwide constraint to common bean (Phaseolus vulgaris L.) production, being photosynthesis one of the most affected physiological processes. To gain insights into the genetic basis of the photosynthetic response of common bean under water-limited conditions, a collection of 158 Portuguese accessions was grown under both well-watered and water-deficit regimes. Leaf gas-exchange parameters were measured and photosynthetic pigments quantified. The same collection was genotyped using SNP arrays, and SNP-trait associations tested considering a linear mixed model accounting for the genetic relatedness among accessions. A total of 133 SNP-trait associations were identified for net CO2 assimilation rate, transpiration rate, stomatal conductance, and chlorophylls a and b, carotenes, and xanthophyll contents. Ninety of these associations were detected under water-deficit and 43 under well-watered conditions, with only two associations common to both treatments. Identified candidate genes revealed that stomatal regulation, protein translocation across membranes, redox mechanisms, hormone, and osmotic stress signaling were the most relevant processes involved in common bean response to water-limited conditions. These candidates are now preferential targets for common bean water-deficit-tolerance breeding. Additionally, new sources of water-deficit tolerance of Andean, Mesoamerican, and admixed origin were detected as accessions valuable for breeding, and not yet explored.

[Significance of family assessment and biological markers in the prevention of arterial hypertension]

OBJECTIVE

To verify the predictability of the appearance of hypertension through the clinical history and biological markers.

POPULATION

Consisted of 300 Portuguese Caucasian individuals, M = 130 and F = 170, between the ages 18 and 85, including 90 pregnant women.

METHODS

Blood pressure was measured in every individual, and questions were made concerning personal and familiar hypertensive background. The serum renin activity, the active renin, serum endoxin, and the urinary aldosteron, free dopamine, c--AMP, and noradrenalin were checked. The analysis of the results was carried ou using the Student's T Test and de chi(2) method.

RESULTS AND CONCLUSIONS

Hypertensive parents lead to the development of hypertension on their descendants; the averages of diastolic blood pressure in normotensive individuals are higher when parents are hypertensive, compared with normotensive, seeming that a possible genetic factor may be implied in the involvement of the vessels. Normotensive young masculine adultshave higher average systolic blood pressure when their fathers are hypertensive, than those whose fathers have normal blood pressure levels; as far as young women are concerned, we verified that the mother's genetic influence seems to be relevant in the appearance of higher blood pressure levels in their daughters during pregnancy, contributing to think hat man and women may have genetically different factors to determine blood pressure levels. We also verified that young adults with normal levels of blood pressure, whose parents suffer from high blood pressure, present significantly higher levels of serum renin activity than a similar group of young adults whose parents have normal blood pressure. We concluded that the family history and the measuring of the blood pressure even at young adults may contribute for the forecasting of high blood pressure, as is the evaluation of biological parameters, particularly in those who have family history of hypertension. Serum renin activity may be a possible biological marker for the forecast of the future development of high blood pressure.