Loss-of-function of triacylglycerol lipases are associated with low flour rancidity in pearl millet [Pennisetum glaucum (L.) R. Br.]

Aher, R R and Palakolanu, S R and Bhunia, R K and Flyckt, K S. and Shankhapal, A R and Ojha, R and Everard, J D and Wayne, L L and Ruddy, B M and Deonovic, B and Gupta, S K and Sharma, K K and Bhatnagar-Mathur, P (2022) Loss-of-function of triacylglycerol lipases are associated with low flour rancidity in pearl millet [Pennisetum glaucum (L.) R. Br.]. Frontiers in Plant Science (TSI), 13 (962667). pp. 1-13. ISSN 1664-462X

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Abstract

Pearl millet is an important cereal crop of semi-arid regions since it is highly nutritious and climate resilient. However, pearl millet is underutilized commercially due to the rapid onset of hydrolytic rancidity of seed lipids post-milling. We investigated the underlying biochemical and molecular mechanisms of rancidity development in the flour from contrasting inbred lines under accelerated aging conditions. The breakdown of storage lipids (triacylglycerols; TAG) was accompanied by free fatty acid accumulation over the time course for all lines. The high rancidity lines had the highest amount of FFA by day 21, suggesting that TAG lipases may be the cause of rancidity. Additionally, the high rancidity lines manifested substantial amounts of volatile aldehyde compounds, which are characteristic products of lipid oxidation. Lipases with expression in seed post-milling were sequenced from low and high rancidity lines. Polymorphisms were identified in two TAG lipase genes (PgTAGLip1 and PgTAGLip2) from the low rancidity line. Expression in a yeast model system confirmed these mutants were non-functional. We provide a direct mechanism to alleviate rancidity in pearl millet flour by identifying mutations in key TAG lipase genes that are associated with low rancidity. These genetic variations can be exploited through molecular breeding or precision genome technologies to develop elite pearl millet cultivars with improved flour shelf life.

Item Type: Article
Divisions: Global Research Program - Accelerated Crop Improvement
CRP: UNSPECIFIED
Uncontrolled Keywords: Pearl millet, Pennisetum glaucum (L.) R. Br., Millet, Milled flour, Lipase, triacylglycerol, rancidity, shelf life
Subjects: Mandate crops > Millets > Pearl Millet
Depositing User: Mr Ramesh MNR
Date Deposited: 11 Oct 2022 16:22
Last Modified: 12 Oct 2022 15:17
URI: http://oar.icrisat.org/id/eprint/12016
Official URL: https://doi.org/10.3389/fpls.2022.962667
Projects: UNSPECIFIED
Funders: RA and RB acknowledge fellowship support from the Department of Science and Technology in the form of INSPIRE fellowship (DST/INSPIRE/03/2018/000417) and INSPIRE Faculty award (DST/INSPIRE/04/2017/000484), respectively. PB-M acknowledges the financial...
Acknowledgement: Authors thank Central Instrumentation Facility (CIF)-NABI for providing key instruments used during the study. Thanks to Joe Shambaugh for assistance with workflow development on the Genedata Expressionist software platform. Authors also thank Günther Daum, Graz University of Technology for kindly providing the yeast lipase-mutant strain.
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