The functions of caspase in whitefly Bemisia tabaci apoptosis in response to ultraviolet irradiation

Abstract

Whiteflies (Bemisia tabaci) are phloem feeders, and some invasive species are composed of cryptic species complexes that cause extensive crop damage, particularly via the direct transmission of plant viruses. Apoptosis is a type of programmed cell death essential for organismal development and tissue homeostasis. The caspases belong to a family of cysteine proteases that play a central role in the initiation of apoptosis in many organisms. Here, we employed a comprehensive genomics approach to identity caspases in B. tabaci Middle East Asia Minor 1 (MEAM1), an invasive whitefly that carries a cryptic species complex that is devastating to crops. Four caspase genes were identified, and their motif compositions were predicted. Structures were relatively conserved in both putative effector and initiator caspases. Expression patterns of caspase genes differed across insect developmental stages. Three caspase genes were induced immediately after ultraviolet (UV) treatment. Expression levels of Bt-caspase-1 and Bt-caspase-3b increased in the midgut and salivary glands during apoptosis induced by UV treatments, whereas silencing of both genes reduced UV-triggered apoptosis. Our study demonstrates that Bt-caspase-1 and Bt-caspase-3b, respectively, act as putative initiator and effector apoptotic caspases in the MEAM1 whitefly.

Apoptotic neurodegeneration in whitefly promotes the spread of TYLCV

“…( Bredesen et al, 2006 ; Fan et al, 2017 ; Jellinger, 2001 ). Only two caspase genes have been characterized in the genome of whitefly, namely, BtCaspase1 and BtCaspase3b , which were demonstrated to be involved in cell death to initiate apoptotic response to UV stress ( Wang et al, 2018 ). Acquiring virions from tomato plants and tobacco plants, and artificial diet, respectively, upregulated the gene transcripts of BtCaspase1 and BtCaspase3b , both in the whole body and head of whitefly ( Figure 2C–D , Figure 2—figure supplement 1C ).…”

“…Similar to mammals, caspase-dependent CNS cell death is also responsible for TYLCV-induced neurodegeneration ( Wang et al, 2018 ). For virus-vector interactions, apoptosis is an effective weapon of the innate immunity to eliminate the virus infection, replication, and dissemination within the insect vector ( Chen and Wei, 2019 ).…”

Structural characterization of ginseng cyclopeptides and detection of capability to induce apoptosis in gastrointestinal cancer cells

“…The activation of the caspases can be achieved by activating the mitogen-activated protein kinase (MAPK) pathway which includes the ERK, JNK and p38 families. 4 Stimulation of the MAPK pathway, and so phosphorylation, can affect the expression of transcription factors such as Bcl-2 and p53, and activate the caspase family, leading to the initiation of apoptosis. 5 As reported, the thioredoxin (Trx)/thioredoxin reductase (TrxR) system is highly expressed in many primary tumors, such as hepatocellular carcinoma.…”

The Bactrocera dorsalis caspase‐1 gene is expressed throughout development and required for female fertility

“…[40][41][42] UV irradiation is used to activate the DNA damage pathway. The caspase-1 was transcriptionally upregulated in Bemisia tabaci, 43 but post-transcriptionally in S. littoralis in response to UV irradiation. 34 Our result showed that Bdcp-1 was transcriptionally upregulated upon UV irradiation, suggesting that Bdcp-1 was involved in the apoptotic stimuli induced by UV irradiation.…”