Plant growth-promoting actinobacteria: a new strategy for enhancing sustainable production and protection of grain legumes

Grain legumes are a cost-effective alternative for the animal protein in improving the diets of the poor in South-East Asia and Africa. Legumes, through symbiotic nitrogen fixation, meet a major part of their own N demand and partially benefit the following crops of the system by enriching soil. In realization of this sustainability advantage and to promote pulse production, United Nations had declared 2016 as the “International Year of pulses”. Grain legumes are frequently subjected to both abiotic and biotic stresses resulting in severe yield losses. Global yields of legumes have been stagnant for the past five decades in spite of adopting various conventional and molecular breeding approaches. Furthermore, the increasing costs and negative effects of pesticides and fertilizers for crop production necessitate the use of biological options of crop production and protection. The use of plant growth-promoting (PGP) bacteria for improving soil and plant health has become one of the attractive strategies for developing sustainable agricultural systems due to their eco-friendliness, low production cost and minimizing consumption of non-renewable resources. This review emphasizes on how the PGP actinobacteria and their metabolites can be used effectively in enhancing the yield and controlling the pests and pathogens of grain legumes

Comparison of the biology, dynamics, and secondary production of Talorchestia brito (Amphipoda, Talitridae) in Atlantic (Portugal) and Mediterranean (Tunisia) populations

The biology, population dynamics, and production of Talorchestia brito were studied at two sandy beaches located on the Atlantic (Portugal) and on the Mediterranean (Tunisia) coasts, respectively. The seasonal variation in abundance and the overall densities were similar in both populations. Reproduction occurred from February to September in the Atlantic, and from March to early November in the Mediterranean. The sex ratio was male biased in the Atlantic, and female biased in the Mediterranean. Based on data from the Atlantic population, both abundance and the proportion of reproductive females were positively correlated with temperature, while the proportion of juveniles in the population was positively correlated with temperature and sediment moisture. On average, individuals from the Atlantic were larger than the ones from the Mediterranean. Life span was estimated at six to nine months in the Atlantic, and five to eight months in the Mediterranean. Talorchestia brito was shown to be a semiannual species, with iteroparous females producing two broods per year, and exhibited a bivoltine life cycle. The minimum age required for males' and females' sexual differentiation and for female sexual maturation was shorter in the Mediterranean. Growth production (P) was estimated at 0.19 g m-2 y-1 ash free dry weight (AFDW; 4.3 kJ m-2 y-1) in the Atlantic population, and 0.217 g m-2 y-1 AFDW (4.9 kJ m-2 y-1) in the Mediterranean one. Elimination production (E) was estimated at 0.35 g m-2 y-1 AFDW (7.9 kJ m-2 y-1) in the Atlantic, and 0.28 g m-2 y-1 AFDW (6.3 kJ m-2 y-1) in the Mediterranean. The average annual biomass () (standing stock) was estimated at 0.032 g m-2 in the Atlantic beach, and 0.029 g m-2 in the Mediterranean one, resulting, respectively, in ratios of 5.9 and 7.5 and ratios of 10.8 and 9.6. Like other talitrids, T. brito exhibited geographic variation in morphometrical characteristics, sex ratio, growth rates, life span, and reproduction period, with the Atlantic population presenting a slower life history.http://www.sciencedirect.com/science/article/B6WDV-49W2MK0-8/1/00a2b4f13d40cd8c6d6f3968e658134

Comparison of Talitrus saltator (Amphipoda, Talitridae) biology, dynamics, and secondary production in Atlantic (Portugal) and Mediterranean (Italy and Tunisia) populations

Talitrus saltator biology, population dynamics, and reproduction were studied more or less simultaneously at three sand beaches: Lavos, on the western coast of Portugal; Collelungo, on the Italian coast of the Thyrrenian Sea; and Zouara, on the northern coast of Tunisia. The species exhibited a consistent pattern of aggregated distribution. Densities were higher at Lavos than at Collelungo and Zouara. Reproduction took place from early March to late September at Lavos and Collelungo, and from late February to early November at Zouara. The average sex ratio was favourable to males at Lavos and Collelungo, and to females at Zouara. Based on data from Lavos, the population abundance was positively correlated with temperature, while the percentage of juveniles in the population was positively correlated with temperature and sediment moisture. Adult individuals from the Atlantic population were larger than the Mediterranean ones, while newborn individuals from the Mediterranean were slightly larger than Atlantic ones. Life span was estimated at 7-11 months at Lavos, 6-9 months at Collelungo, and 6-8 months at Zouara. Cohorts born at the beginning of the reproductive period tend to have shorter lives than the ones born later in the season, with longer life spans occurring in cohorts that crossed the winter to breed in the next year. The minimum period necessary for sexual differentiation after birth was estimated at ±4 weeks at Lavos, ±3 weeks at Collelungo, and ±4.5 weeks at Zouara, for males, and ±6 weeks at Lavos, and ±5 weeks at Collelungo and Zouara, for females. The period necessary for female's sexual maturation after being born was estimated at ±10 weeks at Lavos, and ±8 weeks at Collelungo and Zouara. At the studied sites, T. saltator appeared as semiannual species, with iteroparous females appearing to produce at least two broods per year, and exhibited a bivoltine life cycle. Growth production (P) was estimated at 0.74 g m-2 yr-1 ash-free dry weight (AFDW; 17.7 kJ m-2 yr-1) at Lavos, 0.12 g m-2 yr-1 AFDW (2.8 kJ m-2 yr-1) at Collelungo, and 0.61 g m-2 yr-1 AFDW (14.3 kJ m-2 yr-1) at Zouara. Elimination production (E) was estimated at 1.40 g m-2 yr-1 AFDW (33.5 kJ m-2 yr-1) at Lavos, 0.20 g m-2 yr-1 AFDW (4.8 kJ m-2 yr-1) at Collelungo, and 1.11 g m-2 yr-1 AFDW (26.6 kJ m-2 yr-1) at Zouara. The average annual biomass (standing stock) was estimated at 0.13 g m-2 at Lavos, 0.014 g m-2 at Collelungo, and 0.084 g m-2 at Zouara, resulting in ratios of 5.7 at Lavos, 8.2 at Collelungo, and 7.3 at Zouara, and ratios of 10.8 at Lavos, 14.4 at Collelungo, and 13.1 at Zouara. The present results, combined with information from literature, revealed a geographic variation in T. saltator populations with regard to their morphological characteristics, growth rates, life spans, and life cycles.http://www.sciencedirect.com/science/article/B6WDV-49MX2B2-4/1/246b74442a06ae18a59622e1fc1d71a

Isolation and characterization of non-Frankia actinobacteria from root nodules of alnus glutinosa, casuarina glauca and elaeagnus angustifolia

Actinobacterial isolates randomly obtained on nitrogen-free BAP medium from surface sterilized root nodules of Alnus glutinosa, Casuarina glauca and Elaeagnus angustifolia sampled from fields were reported. They were assigned on the basis of partial 16S rRNA sequences to Micromonospora, Nocardia and Streptomyces genera. The isolates have been screened for hydrolytic activities, indole acetic acid (IAA) and siderophores production, phosphate solubilization and antagonistic activities. Results suggest putative traits as plant growth promoting bacteria proprieties of the isolates that occur in unique association in root nodules of the three analysed actinorhizal host species. © Springer Science+Business Media B.V. 2009