Navigation Links
How plants sense low oxygen levels to survive flooding

RIVERSIDE, Calif. As countries such as Pakistan, Bangladesh, Vietnam and parts of the United States and United Kingdom have fallen victim to catastrophic flooding in recent years, tolerance of crops to partial or complete submergence is a key target for global food security. Starved of oxygen, crops cannot survive a flood for long periods of time, leading to drastic reductions in yields for farmers.

Experts at the University of California, Riverside and The University of Nottingham now report they have discovered how plants sense low oxygen levels to survive flooding a finding that could lead eventually to the production of high-yielding, flood-tolerant crops, benefiting farmers, markets and consumers everywhere.

Specifically, the researchers identified the molecular mechanism involved. This mechanism controls key plant proteins, causing them to be unstable when oxygen levels are normal. When roots or shoots are flooded and oxygen levels drop, these proteins become stable.

"When a plant cell is starved for oxygen, it cannot efficiently generate adenosine triphosphate or ATP, the high-energy molecule plants use for energy storage," explained Julia Bailey-Serres, one of the key researchers participating in the study and a professor of genetics in the Department of Botany and Plant Sciences at UC Riverside. "Because the plant cannot generate enough energy to sustain normal growth, it tries a different approach: it taps into its energy reserves, resulting in more sugars breaking down, as opposed to when oxygen is available, in order to produce ATP. These subtle changes in metabolism are characteristic of low oxygen stress in plant and animal cells. It's similar to the production of lactic acid in our bodies when we exercise. We produce lactic acid as a by-product because we are not producing energy aerobically."

The study describing the oxygen-sensing protein turnover mechanism appears online Oct. 23 in Nature.

"The mechanism controls key regulatory proteins called transcription factors that can turn other genes on and off," explained Michael Holdsworth, a professor of crop science at the University of Nottingham who co-led the research project with Bailey-Serres. "It is the unusual structure of these proteins that destines them for destruction under normal oxygen levels, but when oxygen levels decline, they become stable. Their stability results in changes in gene expression and metabolism that enhance survival in the low oxygen conditions brought on by flooding. When the plants return to normal oxygen levels, the proteins are again degraded, providing a feedback control mechanism."

Bailey-Serres, a member of UCR's Institute for Integrative Genome Biology and an international expert in plant responses to flooding, has been working since 2003 on the cellular mechanisms that regulate submergence tolerance in rice. Her lab has focused on SUB1A, a gene responsible for tolerance of complete submergence in rice and found only in some low-yielding rice varieties in India and Sri Lanka. Her lab is renowned for having characterized the roles of the SUB1A gene that has been bred into modern rice varieties to allow plants to survive two weeks or longer of complete submergence caused by Monsoon rains.

In the current work, the researchers performed their experiments on Arabidopsis, a small flowering plant used widely in plant biology laboratories as a model organism. SUB1A-like proteins are present in other plants, including Arabidopsis. While the protein turnover mechanism targets SUB1A-like proteins in Arabidopsis, the researchers found, to their surprise, that rice SUB1A is resistant to the protein turnover mechanism.

"We think that SUB1A's ability to evade destruction by the protein turnover mechanism under normal oxygen levels may allow it to provide its benefit to submerged rice plants," Bailey-Serres said. "The SUB1A gene is switched on by ethylene gas that accumulates inside cells during submergence. Since the protein does not require a scarcity of oxygen to be stable, it can go to work early to aid the plant."

Holdsworth, an international expert in seed biology and a protein turnover mechanism called the "N-end rule pathway of targeted proteolysis," had the first hint of the discovery while investigating the regulation of gene expression during seed germination. He connected the N-end rule pathway to the Arabidopsis SUB1A-like proteins and their regulation of genes associated with low oxygen stress that Bailey-Serres has studied extensively in Arabidopsis.

"The puzzle pieces fell quickly into place when the expertise of the two teams was combined," he said.

The research team expects that over the next decade scientists will be able to manipulate the protein turnover mechanism in a wide range of crops prone to damage by flooding.


Contact: Iqbal Pittalwala
University of California - Riverside

Related biology news :

1. Plants feel the force
2. Crater shapes explained, how carnivorous plants bite, and doubts about faster-than-light neutrinos
3. Protein plays role in helping plants see light
4. Progress towards developing plants that accommodate climate change
5. Productivity of land plants may be greater than previously thought
6. The breathtaking dance of plants
7. Manipulating plants circadian clock may make all-season crops possible
8. Harnessing the power of plants
9. UBC researchers discover key mechanism that regulates shape and growth of plants
10. Plant biologists dissect genetic mechanism enabling plants to overcome environmental challenge
11. Some plants duplicate their DNA to overcome adversity
Post Your Comments:
Related Image:
How plants sense low oxygen levels to survive flooding
(Date:11/4/2015)... , November 4, 2015 ... market report published by Transparency Market Research "Home Security Solutions ... and Forecast 2015 - 2022", the global home security solutions ... bn by 2022. The market is estimated to expand ... from 2015 to 2022. Rising security needs among customers ...
(Date:10/29/2015)... Oct. 29, 2015  Rubicon Genomics, Inc., today ... distribution of its DNA library preparation products, including ... new ThruPLEX Plasma-seq kit. ThruPLEX Plasma-seq has been ... of NGS libraries for liquid biopsies--the analysis of ... prognostic applications in cancer and other conditions. Eurofins ...
(Date:10/27/2015)... -- Munich, Germany , October ... automatically maps data from mobile eye tracking videos created ... that they can be quantitatively analyzed with SMI,s analysis ... , October 28-29, 2015. SMI,s Automated Semantic Gaze ... tracking videos created with SMI,s Eye Tracking Glasses ...
Breaking Biology News(10 mins):
(Date:11/26/2015)... , November 26, 2015 /PRNewswire/ ... --> Accutest Research Laboratories, ... Contract Research Organization (CRO), has formed ... Cancer Center - Temple Health for ... ,     (Photo: ) , ...
(Date:11/25/2015)... , Nov. 25, 2015  PharmAthene, Inc. (NYSE MKT: ... adopted a stockholder rights plan (Rights Plan) in an ... loss carryforwards (NOLs) under Section 382 of the Internal ... --> PharmAthene,s use of its NOLs could be ... as defined in Section 382 of the Code. In ...
(Date:11/25/2015)... HOLLISTON, Mass. , Nov. 25, 2015 ... a biotechnology company developing bioengineered organ implants for life-threatening ... will present at the LD Micro "Main Event" investor ... PT. The presentation will be webcast live and posted ... also be available at the conference for one-on-one meetings ...
(Date:11/25/2015)... , ... November 25, 2015 , ... ... the Organization of Black Aerospace Professionals (OPBAP) has been formalized with the signing ... AMA team leaders met with OPBAP leaders Capt. Karl Minter and Capt. Albert ...
Breaking Biology Technology: