Paramjit Khurana

Friday Seminar by Dr. Chhavi Agrawal


AG Lab/ Friday/ August 9, 2019/ 3.30 pm/Aldo-Keto Reductase (AKR) as multitasking soldiers : Special reference to role in abiotic stress defense
Category: Research
Posted by: bedineel

Aldo- Keto Reductase (AKR) as multi-tasking soldiers: special reference to role in abiotic stress defense

 

Dr. Chhavi Agrawal

 

Plants are inevitably exposed to a range of environmental fluctuations including water deficit, soil salinization, ultraviolet radiation, high or low temperature etc. These abiotic stressors often cause a rapid and excessive accumulation of reactive oxygen species (ROS), the toxicity of which is further amplified by downstream reactive aldehyde production. Aldo–keto reductase (AKR) is a group of enzymes catalyzing the NAD(P)(H) dependent reduction of a number of carbonyl compounds to corresponding alcohols. In plants, these have been referred as ‘multitasking soldiers’ performing diverse role including reactive aldehyde detoxification, biosynthesis of osmolytes, secondary metabolism, and membrane transport. The majority of plant AKR(s) belong to the AKR4 family; several members of which are known to be stress regulated and have been exploited to produce stress resistant transgenic lines. A positive role of AKR in detoxification of stress-induced reactive carbonyls such as methylglyoxal (MG), HNE and MDA has also been witnessed and linked with its ability to confer tolerance against abiotic stresses. For instance, AKR4C15, rice AKR when ectopically-expressed in Arabidopsis seedlings showed lower levels of both MDA and MG than wild-type seedlings under both normal and stress conditions, emphasizing the role of AKR4C15 in MG and MDA metabolism. Recently, AKR genes from Pseudomonas (PsAKR1) and rice (OsAKR1) were identified as glyphosate-detoxifying genes. PsAKR1- or OsAKRI-expressing tobacco and rice transgenic plants showed improved tolerance to glyphosate with reduced accumulation of shikimic acid without affecting the normal photosynthetic rates. These results suggested that AKR1 when overexpressed detoxifies glyphosate in planta. Thus, plant AKRs can be considered as potential breeding targets for developing stress tolerant varieties in the future.
Suggested Readings:
  1. Sengupta, D., Naik, D., & Reddy, A. R. (2015). Plant aldo-keto reductases (AKRs) as multi-tasking soldiers involved in diverse plant metabolic processes and stress defense: a structure-function update. Journal of plant physiology179, 40-55.
  2. Auiyawong, B., Narawongsanont, R., & Tantitadapitak, C. (2017). Characterization of AKR4C15, a Novel Member of Aldo–Keto Reductase, in Comparison with Other Rice AKR (s). The protein journal36(4), 257-269.
  3. Vemanna, R. S., Vennapusa, A. R., Easwaran, M., Chandrashekar, B. K., Rao, H., Ghanti, K., Sudhakar, C., Mysore, K. S., & Makarla, U. (2017). Aldo‐keto reductase enzymes detoxify glyphosate and improve herbicide resistance in plants. Plant biotechnology journal, 15(7), 794-804.
  4. Agrawal, C., Sen, S., Yadav, S., Rai, S., & Rai, L. C. (2015). A novel aldo-keto reductase (AKR17A1) of Anabaena sp. PCC 7120 degrades the rice field herbicide butachlor and confers tolerance to abiotic stresses in E. coli. PloS one, 10(9), e0137744.