Characterization of Bacillus spp. from the rhizosphere of potato Granola varieties as an antibacterial against Ralstonia solanacearum

Prihatiningsih N, Arwiyanto T, Hadisutrisno B, Widada J. 2020. Characterization of Bacillus spp. from the rhizosphere of potato Granola varieties as an antibacterial against Ralstonia solanacearum. Biodiversitas 21: 4199-4204. Ralstonia solanacearum is one of the important wilt pathogens that significantly decreased potato yields in Indonesia. One of the strategies to control wilt disease is the use of Bacillus sp. that isolated from potato rhizosphere. Bacillus sp. is an antagonist against some phytopathogenic fungi and bacteria. The objectives of the study were to identify 5 strains of Bacillus spp. (B46, B209, B211, B298, and B315) that is capable of suppressing the growth of R. solanacearum. Experimental assays were performed to determine the growth inhibition of R. solanacearum by culturing in a two-layer medium. The identification of Bacillus spp. was performed based on physiological and biochemical characters and molecular identification. Results showed that all of Bacillus spp. are capable of suppressing the growth of R. solanacearum. B. subtilis B315 isolate was the most effective biocontrol agent in inhibiting R. solanacearum growth by a bacteriostatic mechanism. All Bacillus spp. have similarities in physiological and biochemical characters. Based on the molecular analysis, Bacillus sp. B46, B209, B211, and B298 were homologous to B. subtilis subspecies spizizeni RRLKE2, whereas Bacillus sp. B315 was homologous to B. subtilis strain WIFD5.

Influence of Drought Stress on Morphological, Physiological and Biochemical Attributes of Plants: A Review

Drought poses the most significant environmental constrain that limits the growth and yield efficiency of vegetables around the world. The major challenges lies is to identify potential genetic resources and technology development that improve quality and productivity of vegetable crops under declining land, reducing natural resources and increasing environmental stresses. Varied responses of different crop species/genotypes to water-deficit condition have been studied for a long time, and several morphological, physiological and biochemical characters have been suggested to be responsible for drought tolerance. Understanding the morphological, physiological and biochemical responses to drought is essential for a holistic perception of plant resistance mechanisms to water-limited conditions and also to design screening techniques for drought tolerance that may be employed in crop breeding. Drought stress lead to the overproduction of reactive oxygen species (ROS) in plants which inactivate enzymes and damage important cellular components. The effects of the action of free radicals on membranes include the induction of lipid peroxidation and fatty acid de-esterification. Plants possess very efficient enzymatic and non-enzymatic antioxidant defense systems which work in concert to control the cascades of uncontrolled oxidation and protect plant cells from oxidative damage by scavenging of ROS. In this review the important morphological, physiological and biochemical traits that are influenced by drought stress, and may be important indices for identification/screening of drought tolerant genotypes in vegetable crops has been described.

Thermoflavimicrobium dichotomicum as a novel thermoalkaliphile for production of environmental and industrial enzymes

Thermoalkaliphilic actinomycetes enzymes have many important applications in many industrial, biotechnological and environmental aspects. So, the current study aimed to obtain the thermoalkali-enzymes producing actinomycetes. A novel thermoalkaliphilic actinomycete strain was isolated from Egyptian Siwa oasis and identified according to its morphological, physiological and biochemical characters as Thermoflavimicrobium dichotomicum. And then confirmed by phylogenetic analysis and the partial sequence was deposited in GenBank under accession number of KR011193 and name of Thermoflavimicrobium dichotomicum HwSw11. It could produce amylase, cellulase, lipase, pectinase and proteinase enzymes. Also, this strain exhibited anti-bacterial activities against P. aeruginosa and E. coli with inhibition zones of 14 and 20 mm, respectively. Consequently, it has antifungal activity against A. niger, A. flavus and Penicillium notatum with inhibition zones of 17, 14 and 14 mm, respectively. For that, it may be concluded that Thermoflavimicrobium dichotomicum HwSw11 as a novel thermoalkaliphile has a wide range of biological activities against a broad spectrum of pathogenic bacteria and fungi, in addition to produce many enzymes (amylase, cellulase, lipase, pectinase and proteinase). So, this isolate could be applied as manufactory for many industrial, biotechnological and environmental sectors.

The Effects of Zn2+, Cd2+ Pollution on Physiological and Biochemical Characters of Sesbania cannabina Pers.

The Sesbania seedlings experimented, in hydroponic conditions, we studied Zn2+, Cd2+ physiological toxic on Sesbania seedling. The results show that: Zinc and cadmium had a serious effect on poisoning of Sesbania seedlings. With zinc and cadmium Stress concentration increased, Sesbania leaf chlorophyll content showed a trend that increased first and then decreased; Soluble protein content showed a downward trend; proline content showed an upward trend; SOD and POD activity showed increased first and then decreased. Zn2+ and Cd2+ had various effects on toxic intensity, Cd2+ showed a stronger toxic effects.