U.S.-Mexico Cooperative Research: Molecular Characterization of Bacteria Isolated from Casuarina Nodulesin Mexico

小行星9402271 这个美洲计划奖将支持博士安M。赫希，加州大学，洛杉矶，和玛丽亚巴尔德斯博士，国家理工学院，墨西哥，在一个研究合作的固氮共生之间的Frankia微生物菌株和木麻黄树（铁木）。 目的是找到有效的固氮菌株，可用于种植木麻黄，这是一种50年前才引进墨西哥的澳大利亚树木。研究人员的目标是确定在木麻黄根瘤中发现的各种分离物固氮的方式，特别是检查细菌是否具有替代固氮酶基因。 热带和亚热带国家的森林砍伐和可耕地的丧失是全球关注的主要问题。 许多努力，以恢复地区剥夺了树木都失败了，因为脆弱的热带土壤成为枯竭的氮和磷一旦树木被删除。 引进固氮树，也建立菌根关系是解决这个问题的一种方法。 这一项目将使研究人员能够确定能够很好地适应氮耗竭的热带土壤的固氮生物，并可能对土壤侵蚀地区森林大面积砍伐的其他热带和亚热带国家产生影响。 ***

9402271 Hirsch This Americas Program award will support Dr. Ann M. Hirsch, University of California, Los Angeles, and Dr. Maria Valdez, Instituto Politecnico Nacional, Mexico, in a research collaboration on nitrogen-fixing symbiosis between Frankia microbe strains and the Casuarina tree (Ironwood). The objective is to find efficient nitrogen-fixing strains that can be used to inoculate Casuarina, an Australian tree introduced in Mexico only 50 years ago. The researchers aim to determine the means by which various isolates found in nodules of the Casuarina tree fix nitrogen, and, particularly, to examine whether the bacteria have alternative nitrogenase genes. Deforestation and the loss of arable lands in tropical and subtropical countries are major global concerns. Numerous efforts to reclaim areas stripped of trees have failed because the fragile tropical soils become depleted in both nitrogen and phosphorous once the trees are removed. The introduction of nitrogen-fixing trees that also establish mycorrhizal relationships is an approach to this problem. This project will enable researchers to identify nitrogen- fixing organisms that are well adapted for nitrogendepleted tropical soils, and is of potential interest to other tropical and subtropical countries having extensively deforested regions with eroded soils. ***