Length–weight relationships of two fish species from Yalong River,southwestern China

Length–weight relationships (LWRs) were evaluated for Jinshaia sinensis (Sauvage & Dabry de Thiersant, 1874) and Lepturichthys fimbriata (Günther, 1888) using a total of 289 specimens caught by gill nets (mesh size 5.0 cm) and angling in the Yalong River, southwestern China during February and March 2007. This study presents the first reference on LWR for these species from the Yalong River.     

Length–weight relationships of three fish species from the Yangtze River,China

Length–weight relationships (LWRs) were determined for three endemic fish species [Gobiobotia filifer (Garman, 1912), Homatula potanini (Günther, 1896) and Xenophysogobio boulengeri (Tchang, 1929)] from the Yangtze River in China. Samples were obtained between April 2008 and June 2012 using various types of fishing gear and electroshock fishing techniques. For each species, the sample size, length range, weight range, LWR, 95% confidence intervals of a and b, and coefficient of correlation were determined. Prior to this study, the LWRs for two species [Gobiobotia filifer (Garman, 1912) and Homatula potanini (Günther, 1896)] were unknown.     

Pyrophosphate: fructose-6-phosphate 1-phosphotransferase (PFP) regulates carbon metabolism during grain filling in rice

Key message

Decreased PFPase activity in rice perturbs the equilibration of carbon metabolism during grain filling but has no visible phenotypic effects during the vegetative and reproductive growth stages.

Abstract

Starch is a primary energy reserve for various metabolic processes in plant. Despite much advance has been achieved in pathways involved in starch biosynthesis, information was still lacked for precise regulation related to carbon metabolism during seed filling in rice (Oryza sativa). The objective of this study was to identify and characterize new gene associated with carbon metabolism during grain filling. By screening our chemical mutant pool, two allelic mutants exhibiting floury endosperm were isolated. No visible phenotypic defects were observed during both the vegetative and reproductive growth stages, except for the floury-like endosperm of grains with significantly reduced kernel thickness, 1000-grain weight and total starch content. Map-based cloning revealed that the mutant phenotypes were controlled by a gene encoding pyrophosphate: fructose-6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90) β subunit (PFP_β), which catalyzes reversible interconversion between fructose-6-phosphate and fructose-1, 6-bisphosphate. The identity of PFP _β was further confirmed by a genetic complementation test. Subcellular analysis demonstrated that PFPβ was localized in cytoplasm. Quantitative PCR and histochemical staining indicated PFP _β was ubiquitously expressed in various tissues. Furthermore, we found PFP _β could express in both the early and late phases of starch accumulation during grain filling and decreased activity of PFP _β in pfp mutants resulted in compromised carbon metabolism with increased soluble sugar contents and unfavorable starch biosynthesis. Our results highlight PFP_β functions in modulating carbon metabolism during grain filling stage.