title: Effects of high temperature on life history traits and heat shock protein expression in chlorpyrifos-resistant Laodelphax striatella.
abstract: The resistance of the small brown planthopper (SBPH), Laodelphax striatella, to insecticides has been widely found in China, and has posed serious problems to efforts to control the pest. To determine the costs and benefits of resistance, the life tables of chlorpyrifos-resistant and -susceptible strains were constructed at 24 and 30°C. The results showed the resistant SBPH (YN-CPF) had lower fitness at 24°C, but slightly higher fitness at 30°C compared to the susceptible SBPH. Transcriptomic analysis showed there are five heat shock protein genes changed their expression, and the up-regulated genes are LsHsc70-1 and LsHsc70-2. The deduced amino acid sequences of LsHsc70-1 and LsHsc70-2 include three heat shock protein 70 (HSP70) family signatures, but LsHSC70-1 has the conserved HSP70 carboxyl terminal region of the "EEVD" motif, while LsHSC70-2 has the endoplasmic reticulum (ER) retention signal of the "KDEL" motif. The phylogenetic tree further identified LsHsc70-1 has closer evolutionary distances to cytoplasmic/nuclear HSP70s from human and Drosophila melanogaster, while LsHsc70-2 has closer evolutionary distances to HSP70s localized to ER. After treatment at 30-44°C, the expression of LsHsc70-1 and LsHsc70-2 was slightly increased in YN-CPF. These results suggested that LsHsc70-1 and LsHsc70-2 are members of Hsc70 family, localized to the cytosol/nucleus and ER, respectively. The up-regulated expression of these genes may protect the chlorpyrifos-resistant pest against damage under high temperatures, increasing its relative fitness, but the lower relative fitness of this population under optimal temperature may be the trade-off.
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing 210014, China. Electronic address: yangwlh@163.com.
authors.forename: Lihua
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing 210014, China; College of Plant Protection, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Shan
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing 210014, China.
authors.forename: Yueliang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, 1 Weigang, Nanjing 210095, China.
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing 210014, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing 210014, China.
authors.forename: Zhichun
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing 210014, China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Fang
mesh_terms: D000818:Animals; D004390:Chlorpyrifos; D005260:Female; D005298:Fertility / Q000235:genetics; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D006430:Hemiptera / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D006358:Hot Temperature / Q000009:adverse effects*; D019476:Insect Proteins / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides; D000071421:Life History Traits; D008297:Male
chemical_list: D018840:HSP70 Heat-Shock Proteins; D019476:Insect Proteins; D007306:Insecticides; D004390:Chlorpyrifos
keywords: Chlorpyrifos; Fitness; Heat shock protein 70; Resistance