Cloning and expression of genes encoding heat shock proteins in Liriomyza trifolii and comparison with two congener leafminer species

Abstract

The polyphagous agromyzid fly, Liriomyza trifolii, is a significant and important insect pest of ornamental and vegetable crops worldwide. The adaptation of insects to different environments is facilitated by heat shock proteins (HSPs), which play an important role in acclimation to thermal stress. In this study, we cloned and characterized five HSP-encoding genes of L. trifolii (Lthsp20, Lthsp40, Lthsp60, Lthsp70, and Lthsp90) and monitored their expression under different thermal stresses using real-time quantitative PCR. Pupae of L. trifolii were exposed to 19 different temperatures ranging from -20 to 45°C. The results revealed that Lthsp20, Lthsp40, Lthsp70 and Lthsp90 were significantly upregulated in response to both heat and cold stress, while Lthsp60 was induced only by heat temperatures. The temperatures of the onset (Ton) and maximal (Tmax) expression of the five Lthsps were also determined and compared with published Ton and Tmax values of homologous genes in L. sativae and L. huidobrensis. Although L. trifolii occurs primarily in southern China, it has cold tolerance comparable with the other two Liriomyza species. Based on the heat shock proteins expression patterns, L. trifolii has the capacity to tolerate extreme temperatures and the potential to disseminate to northern regions of China.

Molecular Cloning and Characterization of Small Heat Shock Protein Genes in the Invasive Leaf Miner Fly, Liriomyza trifolii

“…We have previously characterized the expression pattern of LtHSP21.3 under temperature stresses [13]. In this study, for comparison, the expression pattern of LtHSP21.3 was also investigated at different developmental stages.…”

“…Total RNA (0.5 μg) was reverse-transcribed into first-strand cDNA using the Bio-Rad iScript™ cDNA Synthesis Kit (Bio-Rad, CA, USA). The RT-qPCR reactions were performed using a CFX96 Real-Time PCR System (Bio-Rad Laboratories, Berkeley, CA, USA) in 20 μL reaction volume, as previously described [13]. The relative quantifications of LtsHSP s were assessed using the 2 − ΔΔCt method [45] and ACTIN was used as a reference gene, because it is commonly used and the most optimal reference gene in L. trifolii under different experimental conditions [43].…”

“…L. sativae is the dominant species and has been detected throughout the country, whereas L. huidobrensis only occurs in regions of relatively high altitude [11,12]. L. trifolii mostly occurs in southeast coastal regions, but recently has been identified in certain northern provinces as well [7,13]. Temperature, particularly low temperature, appears to be the most important environmental factor that affects the distribution of Liriomyza species [8].…”

“…In L. sativae , the expression of sHSPs during development has been investigated and the transcription of LsHSP19.5 , LsHSP20.8, and LsHSP21.7 peaks during the pupal stage [42]. In L. trifolii, the expression profile of LtHSP21.3 has been shown to be similar to those of homologous genes in congeneric species under different temperature treatments [13]. When used to evaluate the stability of reference genes, expression of LtHSP21.7 is shown to be induced by temperature stresses and is varied at different developmental stages [43].…”

Revalidation of morphological characteristics and multiplex PCR for the identification of three congener invasive Liriomyza species (Diptera: Agromyzidae) in China

“…can lead to serious crop losses. Accurate identification of Liriomyza is important for implementing effective control strategies, because insecticide resistance and tolerance to environmental stress varies among species ( Chang et al, 2017 ; Gao et al, 2017 ).…”