H. Kausar

Plant Growth-Promoting Rhizobacteria Enhance Salinity Stress Tolerance in Okra through ROS-Scavenging Enzymes

Salinity is a major environmental stress that limits crop production worldwide. In this study, we characterized plant growth-promoting rhizobacteria (PGPR) containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase and examined their effect on salinity stress tolerance in okra through the induction of ROS-scavenging enzyme activity. PGPR inoculated okra plants exhibited higher germination percentage, growth parameters, and chlorophyll content than control plants. Increased antioxidant enzyme activities (SOD, APX, and CAT) and upregulation of ROS pathway genes (CAT, APX, GR, and DHAR) were observed in PGPR inoculated okra plants under salinity stress. With some exceptions, inoculation with Enterobacter sp. UPMR18 had a significant influence on all tested parameters under salt stress, as compared to other treatments. Thus, the ACC deaminase-containing PGPR isolate Enterobacter sp. UPMR18 could be an effective bioresource for enhancing salt tolerance and growth of okra plants under salinity stress.

Separation and Identification of Volatile Compounds from Liquid Cultures of Trichoderma harzianum by GC-MS using Three Different Capillary Columns

A simple, fast, repeatable and less laborious sample preparation protocol was developed and applied for the analysis of biocontrol fungus Trichoderma harzianum strain FA1132 by using gas chromatography-mass spectrometry. The match factors for sample spectra with respect to the mass spectra library of fungal volatile compounds were determined and used to study the complex hydrocarbons and other volatile compounds, which were separated by using different capillary columns with nonpolar, medium polar and high polar stationary phases. To date, more than 278 volatile compounds (with spectral match factor at least 90%) such as normal saturated hydrocarbons (C7-C30), cyclohexane, cyclopentane, fatty acids, alcohols, esters, sulfur-containing compounds, simple pyrane and benzene derivatives have been identified. Most of these compounds have not previously been reported. The method described in this paper is a more convenient research tool for the detection of volatile compounds from the cultures of T. harzianum.

Physical, chemical and biological changes during the composting of oil palm frond

An experiment was conducted to evaluate the physiochemical and biological changes occurred during the composting process of oil palm fronds (OPF) composts. Compost A, B and C were prepared by mixing OPF, chicken manure (CM) and rice bran (RB) at ratio of 40:40:20, 40:30:30 and 40:20:40, respectively. After day 21, the lowest C/N ratio and the highest amount of nitrogen (N), phosphorus (P) and potassium (K) were recorded in compost A with the values of 15.79, 2.33, 2.02 and 1.80, respectively. Compost A was also found to contain the highest number of bacteria throughout the composting process than that of other two composts suggesting that after day 21, OPF compost A was matured enough to be used as soil amendments to agricultural fields.

Molecular characterization of stress tolerant plant growth promoting rhizobacteria (PGPR) for growth enhancement of rice.

The study was undertaken to characterize plant growth promoting rhizobacteria (PGPR) for growth enhancement and stress tolerant traits and their efficacy on early establishment of rice seedling. In vitro growth promoting traits revealed that out of 30 PGPR isolates, 18 fixed nitrogen, 17 solubilized tri-calcium phosphate, 29 and 17 produced IAA with or without addition of L-tryptophane. In case of stress tolerant activities, PGPR isolates tolerated pH ranging from 5 to 10, Nacl from 1 to 6% and polyethylene glycol (PEG) from 10 to 40%, respectively. They showed antagonistic activity against Pyricularia oryzae with PIRG values ranging from 7−68%. After two-stage of screening, isolates UPMR7 and UPMR17 were identified based on 16s rRNA gene sequences and matched to the genus Bacillus and Citrobacter with 97−98% similarity. UPMR 7 and UPMR 17 were further evaluated on early growth promotion of rice variety MR219. Results revealed that PGPR inoculation had significant effects on plant growth compared to non-inoculated plants. Thus, it could be suggested that the isolates UPMR7 and UPMR17 have the potential to be used as biofertilizer and bioenhancer in sustainable rice cultivation.

Bio-Efficacy of Microbial Infused Rice Straw Compost on Plant Growth Promotion and Induction of Disease Resistance in Chili

ABSTRACT Microbial fortified organic amendment in chili cultivation may affect plant development and disease suppression. Microbial infused rice straw compost, commercial rice straw compost, and fungicide Benomyl for chili (Capsicum annum L.) cultivation and control of Sclerotium foot rot were studied under glass house condition. Chili seed cv. Kulai were sown in the Sclerotium rolfsii infested and non-infested soil. After two weeks, five healthy seedlings were transplanted into planting bags. Growth performance and development of disease symptoms associated with S. rolfsii foot rot infection were assessed. Applying microbial infused rice straw compost increased seed germination and plant growth, and suppressed development of foot rot compared to using commercial rice straw compost and the Benomyl. A higher disease reduction (84.6%) occurred with 15 Mg · ha−1 microbial infused rice straw compost (62.7%), followed by Benomyl (53.8%), and 15 Mg · ha−1 commercial rice straw compost (46.2%). Application of microbial infused rice straw compost at 15 Mg · ha−1 yielded optimum seed germination and seedling establishment, plant growth, and disease suppression. Microbial infused rice straw compost is a good alternative to chemical fungicide in controlling Sclerotial disease in chili.

Development of a potential lignocellulolytic resource for rapid bioconversion of rice straw

This study was conducted at the Laboratory of Food Crops and Floriculture, Institute of Tropical Agriculture, Universiti Putra Malaysia to characterize the potential lignocellulolytic bacteria for rapid bio-bioconversion of rice straw. Fifty isolates of bacteria were isolated from several in-situ and in-vitro sources. Isolates B3, B13, B21, B37 and B46 showed the highest enzymatic activities to starch, carboxymethyl cellulose (CMC) and Azure B amended media. They were further screened on rice straw powder (RSP) amended media for their adaptability on rice straw (RST). The isolate B37 obtained from thermophilic phase of in vitro composting of rice straw and showing the optimum lignocellulolytic activity and adaptation to RSP amended media was identified as Bacillus pumilis . Key words: Rice straw, lignocellulose, microbial degradation, Bacillus pumilis .

Microbial Composting of Rice Straw for Improved Stability and Bioefficacy

Rice is an important cereal crop in the world. Annually, a large amount of straw is produced as by-product from rice cultivation. Proper disposal of rice straw is a concern across the world due to its bulk volume. Composting is an alternative way for recycling of rice straw into a valuable end product for agricultural use. However, composting of rice straw is time consuming as it is composed of lignocellulosic material. Therefore, the aim of this chapter is to summarize the pioneering and recent composting studies and provide information about the uses of potential lignocellulolytic microorganisms in composting as an alternative method for sustainable management of rice straw. In addition, the role of rice straw composts in maintaining of soil health, plant growth promotion and disease suppression as bioenhancer and bioprotectant is discussed. This knowledge could help build a platform for researchers in this area to understand the recent developments in rice straw composting by means of addressing the environmental pollution concerns as well.

Use of Organic Enrichment as Additives in Coconut Coir Dust on Development of Tomato in Soilless Culture

ABSTRACT Amendment of empty fruit bunch (EFB) and vermicompost (VC) in coconut coir dust (CD) has been promoted as a potential alternate media in soilless culture. However, in commercial overview, several problems can be seen in the use of amendment with coconut coir dust as a growth media. The aim of this study was to investigate the effect of EFB and VC as organic amendment (10%–40%; v/v) on the growth and yield of tomato plant in CD media. Six treatments were used with five replications. A 100% CD with nutrient solution (electrical conductivity [EC] = 2.5 mS · cm−1) was used as control treatment. The other treatments were 30 EFB, 10, 20, 30, and 40% VC, which were equivalent to half strength of the nutrients supplied in control. The results showed that plants grown in CD with 20% VC had higher vegetative growth and yield.

Efficient oil palm total RNA extraction with a total RNA extraction kit.

Oil palm tissues are rich in polyphenols, polysaccharides and secondary metabolites; these can co-precipitate with RNA, causing problems for downstream applications. We compared two different methods (one conventional and a kit-based method - Easy-Blue(TM) Total RNA Extraction Kit) to isolate total RNA from leaves, roots and shoot apical meristems of tissue culture derived truncated leaf syndrome somaclonal oil palm seedlings. The quality and quantity of total RNA were compared through spectrophotometry and formaldehyde gel electrophoresis. The specificity and applicability of the protocols were evaluated for downstream applications, including cDNA synthesis and RT-PCR analysis. We found that the conventional method gave higher yields of RNA but took longer, and it was contaminated with genomic DNA. This method required extra genomic DNA removal steps that further reduced the RNA yield. The kit-based method, on the other hand, produced good yields as well as well as good quality RNA, within a very short period of time from a small amount of starting material. Moreover, the RNA from the kit-based method was more suitable for synthesizing cDNA and RT-PCR amplification than the conventional method. Therefore, we conclude that the Easy-BlueTM Total RNA Extraction Kit method is suitable and superior for isolation of total RNA from oil palm leaf, root and shoot apical meristem.