Horizontally transferred genes as RNA interference targets for aphid and whitefly control.

RNA interference (RNAi)-based technologies are starting to be commercialized as a new approach for agricultural pest control. Horizontally transferred genes (HTGs), which have been transferred into insect genomes from viruses, bacteria, fungi or plants, are attractive targets for RNAi-mediated pest control. HTGs are often unique to a specific insect family or even genus, making it unlikely that RNAi constructs targeting such genes will have negative effects on ladybugs, lacewings and other beneficial predatory insect species. In this study, we sequenced the genome of a red, tobacco-adapted isolate of Myzus persicae (green peach aphid) and bioinformatically identified 30 HTGs. We then used plant-mediated virus-induced gene silencing (VIGS) to show that several HTGs of bacterial and plant origin are important for aphid growth and/or survival. Silencing the expression of fungal-origin HTGs did not affect aphid survivorship but decreased aphid reproduction. Importantly, although there was uptake of plant-expressed RNA by Coccinella septempunctata (seven-spotted ladybugs) via the aphids that they consumed, we did not observe negative effects on ladybugs from aphid-targeted VIGS constructs. To demonstrate that this approach is more broadly applicable, we also targeted five Bemisia tabaci (whitefly) HTGs using VIGS and demonstrated that knockdown of some of these genes affected whitefly survival. As functional HTGs have been identified in the genomes of numerous pest species, we propose that these HTGs should be explored further as efficient and safe targets for control of insect pests using plant-mediated RNA interference.

Whole genome sequencing of Asia II 1 species of whitefly reveals that genes involved in virus transmission and insecticide resistance have genetic variances between Asia II 1 and MEAM1 species.

BACKGROUND: Whiteflies (Bemisia tabaci) are phloem sap-sucking pests that because of their broad host range and ability to transmit viruses damage crop plants worldwide. B. tabaci are now known to be a complex of cryptic species that differ from each other in many characteristics such as mode of interaction with viruses, invasiveness, and resistance to insecticides. Asia II 1 is an indigenous species found on the Indian sub-continent and south-east Asia while the species named as Middle East Asia Minor 1 (MEAM1), likely originated from the Middle-East and has spread worldwide in recent decades. The purpose of this study is to find genomic differences between these two species. RESULTS: Sequencing of the nuclear genome of Asia II 1 with Illumina HiSeq and MiSeq generated 198.90 million reads that covers 88% of the reference genome. The sequence comparison with MEAM1 identified 2,327,972 SNPs and 202,479 INDELs. In Total, 1294 genes were detected with high impact variants. The functional analysis revealed that some of the genes are involved in virus transmission including 4 genes in Tomato yellow leaf curl virus (TYLCV) transmission, 96 in Tomato crinivirus (ToCV) transmission, and 14 genes in insecticide resistance. CONCLUSIONS: These genetic differences between Asia II 1 and MEAM1 may underlie the major biological differences between the two species such as virus transmission, insecticide resistance, and range of host plants. The present study provides new genomic data and information resources for Asia II 1 that will not only contribute to the species delimitation of whitefly, but also help in conceiving future research studies to develop more targeted management strategies against whitefly.

Does inclusive leadership influence task performance of hospitality industry employees? Role of psychological empowerment and trust in leader.

Drawing on the social exchange theory, this research advances the understanding of leadership and task performance in the hospitality industry in China by exploring the impact of inclusive leadership on the task performance of subordinates working in dyadic forms. The current literature is scarce on the role of leadership in increasing the task performance of employees working in teams in dyadic forms. Multi-level sample of 410 leaders-subordinates in the hospitality industry was used to derive the research findings using PLS-SEM. The results indicated a positive influence of inclusive leadership on the task performance of subordinates. Psychological empowerment mediated this direct relationship. In addition, trust in leaders strengthened the direct link of inclusive leadership with task performance and psychological empowerment. The findings demonstrate that leaders in the hospitality industry should adopt an inclusive leadership style as it contributes to employee task performance, which improves the industry's performance.

Cotton Mi-1.2-like Gene: A potential source of whitefly resistance.

Whitefly (Bemisia tabaci) inflicts tremendous yield losses to cotton crops in many parts of the world by sap-sucking and transmitting viral diseases. The tomato-associated Mi-1.2 gene has been successfully deployed in tomato cultivars to attain whitefly resistance. In the current study, putative Mi-1.2-like orthologs were identified in five whitefly hosts and functionally validated through virus-inducing gene silencing (VIGS) in cotton plants. The expression profiling and qPCR results depicted differential regulation of the Mi-1.2-like gene in various tissue types and under different biotic and abiotic stresses, especially in whitefly susceptible and resistant cotton plants. The upregulation of the Mi-1.2-like gene (Gadrp RPP-13 Like gene) was observed at 24 h and 48 h post-whitefly exposure (PWFE) in whitefly resistant (FDH-228) and tolerant (Mac7) cotton plants as compared to susceptible plants of Coker-312. However, delayed expression was recorded at 72 h of PWFE in Coker-312 plants. In TRV based gene silencing experiment, silencing of the Mi-1.2-like gene, significantly enhanced the whitefly infestation on both whitefly-resistant and susceptible cotton genotypes. Based on these results, we conducted the evolutionary analysis of Mi-1.2-like orthologs among cotton, cassava, tomato, papaya, and cucumber hosts. This indicated that cotton associated Mi-1.2 like gene has a close relation with cassava and tomato. These results suggested that Mi-1.2-like R genes could be the potential candidate for deriving whitefly resistance response in cotton plants.

Dominance of Asia II 1 species of Bemisia tabaci in Pakistan and beyond.

Globally, Whitefly (Bemisia tabaci) is one of the most important insect pests of crops that causes huge economical losses. The current study was designed to exclusively screen the B. tabaci species in the cotton field of Pakistan during 2017-2020 and have to conduct comparative analysis of B. tabaci species in Asia where Asia II 1 has been reported. A total of 5142 B. tabaci sequences of mitochondrial cytochrome oxidase 1 (mtCO1) from Asian countries were analyzed to determine the species and their distribution in the region. Our analysis over time and space showed that Asia II 1 has gradually dominated over Asia 1 in Punjab Province and over both Asia 1 and MEAM1 in Sindh Province. Asia has been divided into three regions i.e., South Asia (2524 sequences), Southeast Asia (757 sequences) and East Asia (1569 sequences) and dominance of different species of B. tabaci has been determined by calculating the relative percentage of each species. Interestingly, Asia II 1 has been found dominant in the neighboring region (northern zone) of India and also being dominant in its central zone. The dominance of Asia II 1 in Pakistan and northern India explains whitefly epidemic being reported in recent years.