Methylobacterium Enhances Seed Production in Jatropha

Jatropha (Jatropha curcas L.) is a biodiesel crop that can be cultivated on marginal land. However, its seed yield remains low prompting improvements on its seed productivity. Researchers from the National University of Singapore, led by Munusamy Madhaiyan, investigated nitrogen-fixing bacteria in Jatropha to exploit plant–microbe interactions and improve productivity.

Bacterial isolates from Jatropha were evaluated and Methylobacterium species accounted for 69.1% of bacteria in leaves, majority of which were nitrogen-fixing. A Methylobacterium isolate, strain L2-4, was then selected and studied.

Foliar spray of L2-4 led to successful colonization of the surface and internal tissues of leaves. It significantly improved plant height, leaf number, chlorophyll content and stem volume of plants. It also increased female–male flower ratio in plants, resulting in a seed yield increase.

This bacteria–plant interaction may significantly contribute to Jatropha's tolerance to low soil nutrient content. Strain L2-4 opens a new possibility to improve plant's nitrogen supply from the leaves and may be exploited to significantly improve Jatropha's productivity.