Salicylic acid (SA) plays a pivotal role in delaying fruit ripening and senescence.  However, little is known about its underlying mechanism of action.  In this study, RNA sequencing was conducted to analyze and compare the transcriptome profiles of SA-treated and control pear fruits.  We found a total of 159 and 419 genes differentially expressed between the SA-treated and control pear fruits after 12 and 24 h of treatment, respectively.  Among these differentially expressed genes (DEGs), 125 genes were continuously differentially expressed at both treatment times, and they were identified as candidate genes that might be associated with SA-regulated fruit ripening and senescence.  Bioinformatics analysis results showed that 125 DEGs were mainly associated with plant hormone biosynthesis and metabolism, cell wall metabolism and modification, antioxidant systems, and senescence-associated transcription factors.  Additionally, the expression of several candidate DEGs in ripening and senescent pear fruits after SA treatments were further validated by quantitative real-time PCR (qRT-PCR).  This study provides valuable information and enhances the understanding of the comprehensive mechanisms of SA-meditated pear fruit ripening and senescence.

 

Neurotransmitters are important in the maintenance of phase transformation of Locusta migratoria (Arthropoda: Orthoptera).  Here, the effects of the entomopathogen Paranosema locustae on the neurotransmitter taurine in migratory locusts were studied using biochemical methods.  After inoculation with P. locustae, the taurine content of infected locusts significantly declined, but F/C values (ratio between the length of hind femur and the width of the head of locust) increased significantly, compared to healthy locusts.  Meanwhile, F/C values of infected locusts that were injected with 2 µg of taurine showed no significant differences from those of healthy locusts, demonstrating that supplemental taurine inhibited the changes in morphological phase caused by P. locustae.  Paranosema locustae infection also caused longer developmental durations and lower body weights of locusts, but these changes were unaffected after injection with taurine.  These results provided new insights into the mechanisms by which microsporidian parasites affected their locust hosts.