Nitrogen-mediated volatilisation of defensive metabolites in tomato confers resistance to herbivores.

Plants synthesise a vast array of volatile organic compounds (VOCs), which serve as chemical defence and communication agents in their interactions with insect herbivores. Although nitrogen (N) is a critical resource in the production of plant metabolites, its regulatory effects on defensive VOCs remain largely unknown. Here, we investigated the effect of N content in tomato (Solanum lycopersicum) on the tobacco cutworm (Spodoptera litura), a notorious agricultural pest, using biochemical and molecular experiments in combination with insect behavioural and performance analyses. We observed that on tomato leaves with different N contents, S. litura showed distinct feeding preference and growth and developmental performance. Particularly, metabolomics profiling revealed that limited N availability conferred resistance upon tomato plants to S. litura is likely associated with the biosynthesis and emission of the volatile metabolite α-humulene as a repellent. Moreover, exogenous application of α-humulene on tomato leaves elicited a significant repellent response against herbivores. Thus, our findings unravel the key factors involved in N-mediated plant defence against insect herbivores and pave the way for innovation of N management to improve the plant defence responses to facilitate pest control strategies within agroecosystems.

Repair of KuwadaⅡand Ⅲ Achilles tendon defects through modified medial J-shaped approach with autologous fascia lata transplantation / 中国骨伤

OBJECTIVE@#To investigate the clinical effect of modified medial J-shaped incision of Achilles tendon combined with fascia lata transplantation in the treatment of Kuwada typeⅡand Ⅲ Achilles tendon defects.@*METHODS@#From January 2016 to August 2018, the clinical data of 15 patients with KuwadaⅡand Ⅲ Achilles tendon defects treated with modified J-shaped approach with autologous fascia lata transplantation were retrospectively analyzed, including 14 males and 1 female, with an average age of 31.7 years old ranging from 24 to 43. There were 9 cases of KuwadaⅡdefect and 6 cases of KuwadaⅢ defect. Postoperative observations were made for incision complications, and the Arner-Lindholm scoring standard was used to evaluate the function of the affected foot at the last follow-up.@*RESULTS@#All 15 cases were followed up from 3 to 16 months with an average of 9.2 months. No skin necrosis or infection occurred after operation, and no Achilles tendon rupture occurred again. According to the Arner-Lindholm scoring standard, 13 cases were excellent, 2 cases were good.@*CONCLUSION@#Modified medial J-shaped incision is a satisfactory approach for repairing Achilles tendon defects. It is helpful to prevent postoperative incision complications, which double-strengthen the Achilles tendon strength, so that patients can perform early rehabilitation and functional exercises with satisfactory clinical results.