Phosphorus Deprivation Responses and Phosphonate Utilization in a Thermophilic Synechococcus sp. from Microbial Mats

Author:

Adams Melissa M.12,Gómez-García María R.1,Grossman Arthur R.1,Bhaya Devaki1

Affiliation:

1. Carnegie Institution for Science, Department of Plant Biology, Stanford University, Stanford, California 94305

2. Department of Biology, Stanford University, Stanford, California 94305

Abstract

ABSTRACT The genomes of two closely related thermophilic cyanobacterial isolates, designated Synechococcus isolate OS-A and Synechococcus isolate OS-B′, from the microbial mats of Octopus Spring (Yellowstone National Park) have been sequenced. An extensive suite of genes that are controlled by phosphate levels constitute the putative Pho regulon in these cyanobacteria. We examined physiological responses of an axenic OS-B′ isolate as well as transcript abundances of Pho regulon genes as the cells acclimated to phosphorus-limiting conditions. Upon imposition of phosphorus deprivation, OS-B′ stopped dividing after three to four doublings, and absorbance spectra measurements indicated that the cells had lost most of their phycobiliproteins and chlorophyll a . Alkaline phosphatase activity peaked and remained high after 48 h of phosphorus starvation, and there was an accumulation of transcripts from putative Pho regulon genes. Interestingly, the genome of Synechococcus isolate OS-B′ harbors a cluster of phn genes that are not present in OS-A isolates. The proteins encoded by the phn genes function in the transport and metabolism of phosphonates, which could serve as an alternative phosphorus source when exogenous phosphate is low. The phn genes were upregulated within a day of eliminating the source of phosphate from the medium. However, the ability of OS-B′ to utilize methylphosphonate as a sole phosphorus source occurred only after an extensive period of exposure to the substrate. Once acclimated, the cells grew rapidly in fresh medium with methylphosphonate as the only source of phosphorus. The possible implications of these results are discussed with respect to the ecophysiology of the microbial mats.

Publisher

American Society for Microbiology

Subject

Molecular Biology,Microbiology

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3