Genome-wide identification and co-expression analysis of GDSL genes related to suberin formation during fruit russeting in pear

Glycine-aspartic acid–serine-leucine(GDSL)type lipases/esterases genes play critical roles in plant development and are related to the responses to abiotic and biotic stress.However,little is known about the GDSL family in pear(Pyrus spp.).Studies have shown GDSL-domain proteins play key roles in suberin deposition.Suberin deposition in the fruit epidermis,also called russeting,is an important defect that negatively affects consumer's appeal in some fruit species,such as pear,apple and grapevine.Fruit russeting is mainly associated with cuticle microcracking and suberin accumulation in the inner part of the epidermal cell walls.To gain insight into the role of the GDSL gene family in suberin deposition and russet development in pear,we performed a genome-wide characterization of the GDSL family,including their identification,chromosomal localization,phylogenetic relationships,and expression patterns,in different tissues/organs in pear.One hundred and thirteen GDSL-type lipases/esterases genes were identified in the pear genome,and a phylogenetic analysis revealed that GDSL family can be classified into four distinct groups.Thirty GDSL genes were co-expressed with five homolog pear genes of three well-known suberin biosynthesis Arabidopsis genes(AtGPAT5,AtASFT,and AtCYP86B1)in the transcriptional co-expression network during pear fruit development.Among the 30 co-expressed GDSL genes,twelve genes were further analyzed by quantitative Real-time PCR,and the results showed the expression levels of the 12 genes were different between the russet exocarp and green exocarp of sand pear at different fruit development stages.Our study provides a detailed overview of the GDSL gene family and lays the foundation for future functional characterization of GDSL genes in P.bretschneideri.

Last but not the least: effects of laying sequence on egg color variation and embryonic development of Russet Sparrow(Passer cinnamomeus)

Background: Laying sequence has important effects on eggshell color and embryonic development in birds. Some birds can allocate resources unevenly among the eggs within a clutch, prioritizing those at the beginning of the laying sequence, in order to maximize reproductive success. The changes in egg color according to laying sequence may be an adaptation to pressure from predators or brood parasites.Methods: In this study, effects of laying sequence on egg color and embryonic heart rate in Russet Sparrows(Passer cinnamomeus) were investigated using artificial nest boxes. The eggs were divided into three groups: first to be laid, intermediate in the laying sequence, and last to be laid. We maintained the eggs in an incubator and measured embryonic heart rates.Results: Avian visual modeling showed that the background color brightness of the last eggs laid was significantly higher(whiter) than those of the other eggs. All eggs were about the same size and hatched around 13 days, indicating that laying sequence significantly affected embryonic development speed; the last eggs to be laid developed significantly faster than did the first in the clutch.Conclusions: Our study quantified the effect of laying sequence on egg color variation and proved that laying sequence has an important effect on embryonic heart rate in Russet Sparrows.