Plant Developmental Biology and Physiology

Flooding adaption

In rice

 

Adventitious roots

Rice is a semiaquatic plant that is well adapted to flooding. Two important strategies have been described that improve the survival of defined rice types. subm

Deepwater rice escapes complete submergence through rapid elongation of the internode, controlled by several QTLs, including the SNORKEL1 (SK1) and SNORKEL2 (SK2) genes that encode group VII Ethylene Response Factor (ERF) transcription factors.

deepw

adv

Lowland rice has adopted a quiescence strategy that includes repressed shoot growth during submergence and recovery of growth when floods recede. This strategy has also been been attributed to an ERFVII gene, Sub1A. An adaptive trait to flooding observed in both types is the formation of adventitious roots at the stem nodes. We study regulation of adventitious root formation and growth in response to environmental changes in deepwater and lowland rice cultivars.

 

 

 

In Arabidopsis

 

Control of reactive oxygen species

Lack of oxygen leads to regulation of hypoxia genes, some of which encode enzymes of energy metabolism to ensure ATP supply during oxygen deprivation. Without oxygen as a final electron acceptor in the mitochondrial electron transport chain (ETC), the ETC is strongly reduced.

reoxy

In the recovery phase, when plants are re-exposed to air, the reduced ETC can lead to excess ROS formation and to tissue damage as a result. Plants possess an alternative pathway for electron transport in mitochondria that includes alternative NADH dehydrogenases (NDH) and alternative oxidase. We hypothesize that this pathway may control the formation of reactive oxygen species and thus protect mitochondria during the reoxygenation phase. We employ physiological, molecular and cell biological approaches to evaluate the impact of specific NDHs on ROS homeostasis in flooded plants.

 

 

Root system architecture

The group VII Ethylene Response Factors (ERFVIIs) are key transcriptional regulators that regulate metabolic as well as developmental responses to low oxygen stress.

auxin

 

DII

Since roots are the first organs to encounter low oxygen conditions during flooding, we focus our research on dynamic changes in root system architecture. We show that ERFVII-dependent and ERFVII-independent signalling pathways exist that regulate root growth rate, root growth angle and lateral and adventitious root development in response to hypoxia.

DII 2