Factors affecting polygalacturonase gene expression in the tarnished plant bug (Lygus lineolaris)

Polygalacturonase (PG) is an enzyme in the salivary glands of Lygus spp. that is used to break down plant pectins for easier plant tissue feeding and possibly in oviposition site preparation. Previous research has suggested that PG gene expression may change based on the current host of the insect. However, little is known about all the factors that may be involved in PG gene expression regulation. A study using quantitative real time-polymerase chain reaction (qRT-PCR) was used to measure expression levels of three PG genes (PG1, PG2, PG3). Comparisons were made between males and females and at six different times (ZT0, ZT4, ZT8, ZT12, ZT16, ZT20, ZT24; 9am, 1pm, 5pm, 9pm, 1am, 5am)This study shows the effects of PG gene expression caused by circadian rhythm. There was no interaction between time and sex for any of the three PG genes. Time and sex were significant (p<0.05) for PG1 and PG2 while only time was significant for PG3.