Drought responsive genes and their functional terms identified by GS FLX Pyro sequencing in maize

Drought stress is a major challenge for the production of maize (Zea mays L), leading to reduced growth of aerial parts and, to a large extent, reproductive stages of development. We applied the 454 GS FLX titanium platform to identify drought differentially regulated genes in the maize vegetative and reproductive tissues. A total of 2,199 genes of which 1,284 in reproductive and 915 in vegetative tissues were identified by the platform. Quantitative RT-PCR of differentially expressed genes was carried out to confirm their expression. The results showed that the transcripts were correctly assembled and represented actively expressed genes, which genes were further subjected to gene ontology analysis for biological processes, molecular function and cell component functional terms. Significantly enriched terms indicates that catabolism of proteins and maintenance of cellular homeostasis processes were significantly enriched in the vegetative tissues, while on the other hand carbohydrate metabolism was enriched in the reproductive tissues. Photosynthesis, and energy metabolism as well as protein biosynthesis were highly repressed in both tissues. These add to the concept that drought stress target photosynthesis and causes a transition of metabolism from protein synthesis by repressing amino acid biosynthesis and translation to degradation by inducing the ubiquitin-proteasome pathway. Identified genes are potential candidates for maize improvement through transgenic and mutagenic approaches

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SOURCES AND IMPLICATIONS OF RURAL HOUSEHOLD INCOME FOR IMPROVING RURAL ENTREPRENEURSHIP IN AFRICA: EMPIRICAL EVIDENCE FROM BOTSWANA

In many African countries, a high proportion of the population resides in the rural areas and derives their incomes mainly from agriculture. This notwithstanding, there is a growing evidence that incomes from nonfarm employment sources are increasingly becoming important among the rural population. Using Botswana's rural household survey data, this paper examines the relative contributions and implications of agriculture and nonfarm employment to rural household incomes. Contrary to the popular held view that most rural households derive their income mainly from agriculture, the fmdings of this analysis clearly indicate that nonfarm employment is the dominant source of income in the study area. It accounted for 53% of the average total farm-household income of P4787 (1US$ = P2.49). Remittances alone contributed a substantial share of 37% and constitute an important source of income for most households in the area. On average, 40% of each household's labour force were migrant workers. As regards employment in the area, agriculture employed more than 88% of the active labour force in the villages. The relatively low contribution (47%) from agriculture implies that the potential for savings, investment and development of entrepreneur skills among most people in the area is limited. This situation is likely to encourage rapid rural-urban migration of a considerable proportion of the youth in the area. It is suggested that development strategy of Botswana government should concentrate on sustainable agricultural growth and establishment of rural enterprises to increase both income and employment shares of agriculture and non-agricultural activities, respectively, as well as rural entrepreneurshi

Morphological, Physiological, and Molecular Stomatal Responses in Local Watermelon Landraces as Drought Tolerance Mechanisms

Drought-tolerant plants have become a convenient model to study the mechanisms underlying drought tolerance in order to improve susceptible domesticated relatives. Various studies have shown that local landraces possess superior qualities that help them survive in harsh environmental conditions. One of the key mechanisms that helps with tolerance in crops is timely stomatal regulation. In this study, the physiological, morphological, and molecular stomatal responses in three drought-tolerant landraces (Clm-01–03) and hybrid (Clm-04) watermelons were evaluated under drought stress. The watermelon plants were grown under a water deficit (complete withholding of water) and non-stress conditions. The highest SPAD values were recorded for the Clm-03 and Clm-02 (50 ± 3) watermelon genotypes, and the lowest for Clm-04 (27 ± 0.37), showing this genotype’s tolerance and ability to maintain its systems during drought stress. Fluorescence parameters also gave important clues to the tolerant genotypes of Clm-02 and Clm-03 under drought stress, while the domesticated genotype showed a slow response to fluorescence parameters, which could lead to damage to the photosynthesis apparatus. During the drought period, the wild watermelon was found to have a limited stomatal opening as the drought progressed, and on day 9, it had the smallest opening of 23.1 ± 1.2 µm compared to any other genotype; most importantly, upon re-watering, it showed more rapid recovery than any other genotype. This was also expressed by mRNA quantification of stomatal aperture TFs, with an eight-fold increase in Cla004380 TFs recorded for wild watermelon. All of these mechanisms have been attributed to the tolerance mechanisms of the drought-tolerant watermelon genotype. This study provides important insight into the stomatal responses of probable tolerant watermelon accessions and suggests that improving the stomatal aperture of susceptible domesticated species would also improve their tolerance

Decreased diarrheal and respiratory disease in HIV exposed uninfected children following vaccination with rotavirus and pneumococcal conjugate vaccines.

BackgroundRotavirus vaccine (RV) and pneumococcal vaccine (PCV) decrease diarrheal and respiratory disease incidence and severity, but there are few data about the effects of these vaccines among HIV-exposed uninfected (HEU) children.MethodsWe recorded RV and PCV vaccination history in a placebo-controlled trial that studied the need for cotrimoxazole among HEU infants in Botswana (the Mpepu Study). We categorized infants by enrollment before or after the simultaneous April 2012 introduction of RV and PCV, and compared diagnoses of diarrhea and pneumonia (grade 3/4), hospitalizations, and deaths from both disease conditions through the 12-month study visit by vaccine era/status across two sites (a city and a village) by Kaplan-Meier estimates.ResultsTwo thousand six hundred and thirty-five HEU infants were included in this secondary analysis, of these 1689 (64%) were enrolled in Gaborone (344 pre-vaccine, 1345 vaccine) and 946 (36%) in Molepolole (209 pre-vaccine, 737 vaccine). We observed substantial reduction in hazard of hospitalization or death for reason of diarrhea and pneumonia in the vaccine era versus the pre-vaccine era in Molepolole (hazard ratio, HR = 0.44, 95% confidence interval, CI = 0.28, 0.71) with smaller reduction in Gaborone (HR = 0.91, 95% CI = 0.57, 1.45). Similar downward trends were observed for diagnoses of diarrhea and pneumonia separately during the vaccine versus pre-vaccine era.ConclusionsAlthough temporal confounding cannot be excluded, significant declines in the burden of diarrheal and respiratory illness were observed among HEU children in Botswana following the introduction of RV and PCV. RV and PCV may maximally benefit HEU children in rural areas with higher disease burden