Genetic analysis of Na+ and K+ concentrations in leaf and stem as physiological components of salt tolerance in Tomato

International audienceThe sodium and potassium concentrations in leaf and stem have been genetically studied as physiological components of the vegetative and reproductive development in two populations of F 8 lines, derived from a salt sensitive genotype of Solanum lycopersicum cv. Cerasi-forme, as female parent, and two salt tolerant lines, as male parents, from S. pimpinellifolium, the P population (142 lines), and S. cheesmaniae, the C population (116 lines). Genetic parameters of ten traits under salinity and Wve of them under control conditions were studied by ANOVA, correlation, principal component and QTL analysis to understand the global response of the plant. Two linkage maps including some tomato Xowering time and salt tolerance candidate genes encoding for SlSOS1, SlSOS2, SlSOS3, LeNHX1, LeNHX3, were used for the QTL detection. Thirteen and 20 QTLs were detected under salinity in the P and C populations, respectively, and four under control conditions. Highly signiWcant and contributing QTLs (over 40%) for the concentrations of Na + and K + in stems and leaves have been detected on chromosome 7 in both the populations. This is the only genomic position where the concentration QTLs for both the cations locate together. The proportion of QTLs signiWcantly aVected by salinity was larger in the P population (64.3%, including all QTLs detected under control) than in the C population (21.4%), where the estimated genetic component of variance was larger for most traits. A highly signiWcant association between the leaf area and fruit yield under salinity was found only in the C population, which is supported by the location of QTLs for these traits in a common region of chromososome C1. As far as breeding for salt tolerance is concerned, only two sodium QTLs (lnc1.1 and lnc8.1) map in genomic regions of C1 and C8 where fruit yield QTLs are also located but in both the cases the proWtable allele corresponds to the salt sensitive, cultivated species. One of those QTLs, lnc1.1 might involve LeNHX3

IRAP and REMAP for retrotransposon-based genotyping and fingerprinting

v2006okBEL/KG

The Magpie Trial: A randomised trial comparing magnesium sulphate with placebo for pre-eclampsia. Outcome for children at 18 months

Objective: To assess the long-term effects of in utero exposure to magnesium sulphate for children whose mothers had pre-eclampsia. Design: Assessment at 18 months of age for children whose mothers were recruited to the Magpie Trial (recruitment 1998-2001 ISRCTN 86938761), which compared magnesium sulphate with placebo. Setting: Follow-up of children born at 125 centres in 19 countries across five continents. Population: A total of 6922 children were born to women randomised before delivery at follow-up centres. Of these, 2271 were not included for logistic reasons and 168 were excluded (101 at a centre where <20% were contacted, 40 whose death or disability was due to a problem at conception or embryogenesis and 27 whose parent/s opted out). Therefore, 4483 children were included in follow-up, of whom 3283 (73%) were contacted. Methods: Assessment by questionnaire, with interview and neurodevelopmental testing of selected children. Main outcome measures: Death or neurosensory disability at age of 18 months. Results: Of those allocated magnesium sulphate, 245/1635 (15.0%) were dead or had neurosensory disability at 18 months compared with 233/1648 (14.1%) allocated placebo (relative risk [RR] 1.06, 95% CI 0.90-1.25), and of survivors, 19/1409 (1.3%) had neurosensory disability at 18 months compared with 27/1442 (1.9%) (RR 0.72, 95% CI 0.40-1.29). There were no substantial differences in causes of death or in the risk of individual impairments or disabilities. Conclusions: The lower risk of eclampsia following prophylaxis with magnesium sulphate was not associated with a clear difference in the risk of death or disability for children at 18 months. © RCOG 2006 BJOG An International Journal of Obstetrics and Gynaecology.Articl