Two farnesyl pyrophosphate synthases,GhFPS1–2,in Gossypium hirsutum are involved in the biosynthesis of farnesol to attract parasitoid wasps

Sesquiterpenoids play an import role in the direct or indirect defense of plants.Farnesyl pyrophosphate synthases(FPSs)catalyze the biosynthesis of farnesyl pyrophosphate,which is a key precursor of farnesol and(E)-β-farnesene.In the current study,two FPS genes in Gossypium hirsutum,GhFPS1 and GhFPS2,were heterologously cloned and functionally characterized in a greenhouse setting.The open reading frames for full-length GhFPS1 and GhFPS2 were each 1029 nucleotides,and encoded two proteins of 342 amino acids with molecular weights of 39.4 kDa.The deduced amino acid sequences of GhFPS1–2 showed high identity to FPSs of other plants.Quantitative real-time PCR analysis revealed that GhFPS1 and GhFPS2 were highly expressed in G.hirsutum leaves,and were upregulated in methyl jasmonate(MeJA)-,methyl salicylate(MeSA)-and aphid infestation-treated cotton plants.The recombinant proteins of either GhFPS1 or GhFPS2 plus calf intestinal alkaline phosphatase could convert geranyl diphosphate(GPP)or isopentenyl diphosphate(IPP)to one major product,farnesol.Moreover,in electrophysiological response and Y-tube olfactometer assays,farnesol showed obvious attractiveness to female Aphidius gifuensis,which is an important parasitic wasp of aphids.Our findings suggest that two GhFPSs are involved in farnesol biosynthesis and they play a crucial role in indirect defense of cotton against aphid infestation.

Microstructural Evolution during Tensile Deformation in TRC-ZA21 Magnesium Alloy with Different Loading Directions and Strain Rates

The variation of texture characteristics and activation of deformation mechanism in magnesium alloys can be achieved by addition of RE and Ca elements and subsequently affect the microstructure evolution during deformation process.In this manuscript,the effects of loading direction and strain rate on mechanical properties,microstructural characteristics,texture evolution and deformation mechanism in TRC-ZA21 magnesium alloy sheet were investigated.Moreover,orientation dependence and strain rate sensitivity of deformation mechanism were also discussed.The results showed that evident difference in mechanical properties in TRC-ZA21 alloy exhibited by the changes in loading direction and strain rate.The variations in grain orientation and basal texture characteristic were attributed to the grain rotation behavior during the plastic deformation,dominated by deformation mechanism.Basal slip,extension twinning and prismatic slip played different contributions to plastic deformation behavior and presented orientation dependence and strain rate sensitivity.The activities of prismatic slip and extension twinning both enhance with increasing strain rate.The phenomenon of weakened effect of twinning and promoted role of prismatic slip was presented to coordinate strain compatibility during plastic deformation.

Fabrication of Microporous Membranes from Melt Extruded Polypropylene Precursor Films via Stretching: Effect of Annealing

In this work, the effects of annealing conditions on the microstructure of polypropylene（PP） precursor films and further on the porous structure and permeability of stretched membranes were investigated. Combinations of WAXD, FTIR, DSC and DMA results clearly showed the crystalline orientation and crystallinity of the precursor film increased with annealing temperature, while the molecular chain entanglements in the amorphous phase decreased. Changes in the deformation behavior suggested more lamellar separation occurred for the films annealed at higher temperatures. Surface morphologies of the membranes examined by SEM revealed more pore number and uniform porous structure as the annealing temperature increased. In accordance with the SEM results, the permeability of the membranes increased with annealing temperature. On the other hand, it was found that 10 min was almost enough for the annealing process to obtain the microporous membranes with an optimal permeability.