Genetic recombination among tomato yellow leaf curl virus isolates in commercial tomato crops in Kuwait drives emergence of virus diversity: a comparative genomic analysis.

OBJECTIVE: Whitefly-transmitted tomato yellow leaf curl virus (TYLCV) continues to be a major constraint to tomato production in Kuwait. However, very limited information is available about the population structure and genetic diversity of TYLCV infecting tomato in Kuwait. RESULTS: Whole genome sequences of 31 isolates of TYLCV, collected from commercial tomato crops grown in northern (Abdally) and southern (Al Wafra) parts of Kuwait, were deciphered. Eighteen isolates of TYLCV are identified as potential genetic recombinants. The isolates Abdally 6A and Abdally 3B reported in this study were identified to be potential recombinants. Compared to the 15 isolates from the Abdally area, and the three previously reported KISR isolates of Kuwait, six out of sixteen Al Wafra isolates showed an insertion of 19 extra nucleotides near the 5'-end. There are also four nucleotide variations before the 19-extra-nucleotides. The additional 19 nucleotides observed in nine isolates indicate that these isolates might have resulted from a single gene recombination/insertion event. Molecular phylogeny based on complete genome sequences of TYLCV isolates suggests transboundary movement of virus isolates due to geographic proximity. The information presented herein is quite useful for the comprehension of TYLCV biology, epidemiology and would aid in the management of disease in the long run.

Distribution and diversity of eukaryotic microalgae in Kuwait waters assessed using 18S rRNA gene sequencing.

The microbial communities play a crucial role in ecosystem functioning through interactions among individuals and taxonomic groups in a highly dynamic marine ecosystem. The structure and functioning of the microbial communities are often influenced by the changes in the surrounding environment. Monitoring the microbial diversity of the marine ecosystem helps to understand spatial patterns of microbial community and changes due to season, climate, and various drivers of biological diversity. Kuwait is characterized by an arid environment with a high degree of temperature variation during summer and winter. Our understanding of spatial distribution patterns of microbial communities, their diversity, and the influence of human activities on the degree of changes in the diversity of the microbial community in Kuwait territorial waters remain unclear. In this study, we employed 18S rRNA sequencing to explore marine microalgal community composition and dynamics in seawater samples collected from Kuwait waters over two seasonal cycles across six locations. A total of 448,184 sequences across 36 replicates corresponding to 12 samples from six stations were obtained. The quality-filtered sequences were clustered into 1,293 representative sequences, which were then classified into different eukaryotic taxa. This study reveals that the phytoplankton community in Kuwait waters is diverse and shows significant variations among different taxa during summer and winter. Dinoflagellates and diatoms were the most abundant season-dependent microalgae taxa in Kuwait waters. Alexandrium and Pyrophacus were abundant in summer, whereas Gonyaulax was abundant during the winter. The abundance of Coscinodiscus and Navicula, of the diatom genera, were also dependent upon both seasonal and possible anthropogenic factors. Our results demonstrate the effectiveness of a sequencing-based approach, which could be used to improve the accuracy of quantitative eukaryotic microbial community profiles.

Metagenomic analysis of rhizosphere microflora of oil-contaminated soil planted with barley and alfalfa.

The role of rhizosphere microbial communities in the degradation of hydrocarbons remains poorly understood and is a field of active study. We used high throughput sequencing to explore the rhizosphere microbial diversity in the alfalfa and barley planted oil contaminated soil samples. The analysis of 16s rRNA sequences showed Proteobacteria to be the most enriched (45.9%) followed by Bacteriodetes (21.4%) and Actinobacteria (10.4%) phyla. The results also indicated differences in the microbial diversity among the oil contaminated planted soil samples. The oil contaminated planted soil samples showed a higher richness in the microbial flora when compared to that of untreated samples, as indicated by the Chao1 indices. However, the trend was different for the diversity measure, where oil contaminated barley planted soil samples showed slightly lower diversity indices. While the clustering of soil samples grouped the oil contaminated samples within and across the plant types, the clean sandy soil samples formed a separate group. The oil contaminated rhizosphere soil showed an enrichment of known oil-degrading genera, such as Alcanivorax and Aequorivita, later being specifically enriched in the contaminated soil samples planted with barley. Overall, we found a few well known oil-degrading bacterial groups to be enriched in the oil contaminated planted soil samples compared to the untreated samples. Further, phyla such as Thermi and Gemmatimonadetes showed an enrichment in the oil contaminated soil samples, indicating their potential role in hydrocarbon degradation. The findings of the current study will be useful in understanding the rhizosphere microflora responsible for oil degradation and thus can help in designing appropriate phytoremediation strategies for oil contaminated lands.

First complete genomic characterization and phylogeny of a new recombinant of tomato yellow leaf curl virus (genus Begomovirus, family Geminiviridae) from Kuwait.

While whitefly-transmitted begomoviruses are economically important constraints to tomato production in Kuwait, little is known about genomic features of these viruses from Kuwait. A begomovirus isolated from severely diseased tomatoes, collected over a two-year period in the main tomato-growing areas of Kuwait, was characterized at the molecular level. The complete genomic sequence of the begomovirus was determined, and phlylogeographic studies were conducted to better understand genetic diversity of the virus in the region. Based on genome properties and phylogenetic analysis, the begomovirus was found to be a strain of tomato yellow leaf curl virus (TYLCV). The virus genome was monopartite, as neither DNA B nor satellite DNA molecules were detected. Two isolates characterized in this study shared 97% and 95% nucleotide sequence identity with a previously characterized Kuwaiti isolate, TYLCV-KISR. Among TYLCV isolates with known genome sequences, the Kuwaiti isolates shared highest sequence identity (95%) with TYLCV-Almeria (Spain). Genetic diversity and phylogenetic analysis showed that the three Kuwaiti isolates formed a distinct clade that was separate from those of known TYLCV sequences. One Kuwaiti isolate (KW 1-3) could be a novel variant of TYLCV. Two recombination events were detected in the genome sequence of KW 1-3, which appeared to be a recombinant derived from TYLCV parents from Oman and Kuwait.

Detection of genetically modified DNA in fresh and processed foods sold in Kuwait.

Developments in genetic engineering technology have led to an increase in number of food products that contain genetically engineered crops in the global market. However, due to lack of scientific studies, the presence of genetically modified organisms (GMOs) in the Kuwaiti food market is currently ambiguous. Foods both for human and animal consumption are being imported from countries that are known to produce GM food. Therefore, an attempt has been made to screen foods sold in the Kuwaiti market to detect GMOs in the food. For this purpose, samples collected from various markets in Kuwait have been screened by SYBR green-based real time polymerase chain reaction (RT-PCR) method. Further confirmation and GMO quantification was performed by TaqMan-based RT-PCR. Results indicated that a significant number of food commodities sold in Kuwait were tested positive for the presence of GMO. Interestingly, certain processed foods were tested positive for more than one transgenic events showing complex nature of GMOs in food samples. Results of this study clearly indicate the need for well-defined legislations and regulations on the marketing of approved GM food and its labeling to protect consumer's rights.