Abstract
Cassava, being one of the top three tuberous crops, features highly efficient starch accumulation in the storage root to adapt the tropical resources and environments. The molecular mechanism for the process, however, is still unclear. ADP-glucose pyrophosphorylase, the first and rate-limited enzyme in starch biosynthesis pathway, is a heterotetramer comprised of two small/catalytic and two large/modulatory subunits. To understand the regulation of MeAGPase, the promoter of a highly expressed small subunit, MeAGPs1a, was used as bait for a yeast one-hybrid assay to screen storage root cDNA library. One cDNA, coding for a small auxin-up RNA protein, named MeSAUR1, was isolated from cassava. MeSAUR1 could bind to the promoter of MeAGPS1a in yeast one-hybrid test and in vitro, and was located in cell nucleus. MeSAUR1 displayed a higher transcript level in cassava root cortex, and its expression was induced by indole-3-acetic acid, gibberellin and ethylene, but repressed by abscisic acid. A dual-luciferase interaction test further convinced that MeSAUR1 could bind to the promoter of MeAGPS1a, and positively regulate the transcription of MeAGPS1a in cassava.
Highlights
Cassava (Manihot esculenta Crantz), originated from Amazon tropical rainforest in South America, is one of the top three tuberous crops in the global world
The amino acids sequences of Arabidopsis ADP-glucose pyrophosphorylase (AGPase) family genes were used to BLAST in cassava genome database
In order to screen certain transcription factors (TFs) which regulate MeAGPS1a, and understand more about the regulation mechanism of starch biosynthesis in cassava storage root, a yeast one-hybrid assay was performed with the MeAGPS1a promoter as bait and the storage root cDNA library as prey
Summary
Cassava (Manihot esculenta Crantz), originated from Amazon tropical rainforest in South America, is one of the top three tuberous crops in the global world. Cassava storage root/starch is the main staple for African and South American people, and an important source for food processing and bio-energy industry. Starch is an insoluble polymer of glucose residues produced by the majority of higher plant species, and mainly stored in seeds and storage organs (Tetlow et al, 2004). MeSAUR1 Positively Regulates MeAGPS1a biosynthesis pathway, and it consists of two small/catalytic and two large/modulatory subunits as a heterotetramer in higher plants (Ballicora et al, 2004; Saripalli and Gupta, 2015). The AGPase gene family has been characterized in several higher plants, e.g., two small subunits (SS) and several large subunits (LS) in rice and sweet potato, respectively (Akihiro et al, 2005; Zhou et al, 2016). Over-expressing SS gene or/and LS gene could enhance AGPase activity, increase seed weight and starch content (Li et al, 2011)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
