Understanding the genetic basis of phenotypes is of importance in evolutionary biology, and genetic improvement of economic animals. The Giant strain of fighting fish, Betta splendens, provides a unique material for dissecting the genetic architecture of overgrowth of body size because of its giant body size. We re-sequenced and analyzed the genomes of 54 fighting fish. Genome-wide FST and selective sweeps scans using 3,582,429 DNA variants revealed that three genomic regions at chr1, chr9 and chr11 were associated with the giant body size. These regions, with a total length of ~ 3.5 Mb, were highly diverged between the Giant and the non-Giant bettas. In contrast, no signature of selection was detected in the wild type fish. Transcriptome analysis in the brain and muscle samples from Giant and non-Giant betta fish identified 14 candidate genes that were likely responsible for the giant body size. Our data provide novel insight into the genetic basis of body size variation. The genome and transcriptome sequences, DNA sequence variants and candidate genes for body size provide valuable resources for further biological and evolutionary studies, as well as for rapid improvement of growth-related traits.

Oil palm is the most productive oil producing plant. Salt stress leads to growth damage and decrease in yield of oil palm. However, the physiological responses of oil palm to salt stress and their underlying mechanisms are not clear. RNA-Seq for leaf samples from young palms challenged under three levels of salts (100, 250 and 500 mM NaCl) for 14 days and control was conducted. All the three levels of salt stress activated EgSPCH expression and increased stomatal density of oil palm. ~ 41% of DEGs were putative EgSPCH binding target and were involved in multiple bioprocesses related to salt response. Overexpression of EgSPCH in Arabidopsis increased the stomatal production and lowered the salt tolerance. These data indicate that in oil palm, salt activates EgSPCH to generate more stomata in response to salt stress, which is different with that in herbaceous plants. Our results might mirror the difference of salt-induced stomatal development between ligneous and herbaceous crops.