Abstract
Cassava (Manihot esculenta Crantz) demand has been rising because of its various applications. High salinity stress is a major environmental factor that interferes with normal plant growth and limits crop productivity. As well as genetic engineering to enhance stress tolerance, the use of small molecules is considered as an alternative methodology to modify plants with desired traits. The effectiveness of histone deacetylase (HDAC) inhibitors for increasing tolerance to salinity stress has recently been reported. Here we use the HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA), to enhance tolerance to high salinity in cassava. Immunoblotting analysis reveals that SAHA treatment induces strong hyper-acetylation of histones H3 and H4 in roots, suggesting that SAHA functions as the HDAC inhibitor in cassava. Consistent with increased tolerance to salt stress under SAHA treatment, reduced Na+ content and increased K+/Na+ ratio were detected in SAHA-treated plants. Transcriptome analysis to discover mechanisms underlying salinity stress tolerance mediated through SAHA treatment reveals that SAHA enhances the expression of 421 genes in roots under normal condition, and 745 genes at 2 h and 268 genes at 24 h under both SAHA and NaCl treatment. The mRNA expression of genes, involved in phytohormone [abscisic acid (ABA), jasmonic acid (JA), ethylene, and gibberellin] biosynthesis pathways, is up-regulated after high salinity treatment in SAHA-pretreated roots. Among them, an allene oxide cyclase (MeAOC4) involved in a crucial step of JA biosynthesis is strongly up-regulated by SAHA treatment under salinity stress conditions, implying that JA pathway might contribute to increasing salinity tolerance by SAHA treatment. Our results suggest that epigenetic manipulation might enhance tolerance to high salinity stress in cassava.
Highlights
Cassava (Manihot esculenta Crantz) originated in South America and is an important root crop, of which worldwide cultivation has progressed throughout tropical and subtropical regions (Olsen and Schaal, 1999)
AAGI code is shown if proteins encoded in each cassava gene have high amino acid sequence similarity (E ≤ 10−5) to Arabidopsis homologs. bEncoded proteins/other features indicate the putative functions of the gene products that are expected from sequence similarity
We demonstrated that the histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), can decrease sodium ion content in the stems, resulting in increased survival rates under high salinity stress conditions in cassava
Summary
Cassava (Manihot esculenta Crantz) originated in South America and is an important root crop, of which worldwide cultivation has progressed throughout tropical and subtropical regions (Olsen and Schaal, 1999). Previous studies have revealed that several mechanisms such as maintenance of ion homeostasis, accumulation of compatible solutes, hormonal control, antioxidant systems, and Ca2+ signaling are essential for plants to survive under high salinity stress (Jia et al, 2015). Based on those findings, genetic engineering and conventional breeding have been widely used to develop salt-tolerant plants. These include transporters for ion homeostasis such as NHX1 (Apse et al, 1999), SOS1/2/3 (Shi et al, 2003; Yang et al, 2009), and HKT1 (Mølle et al, 2009); and for the accumulation of osmolytes such as proline (Kishor et al, 1995) and glycine betaine (Sakamoto and Murata, 1998); late embryogenesis abundant (LEA) proteins (Xu et al, 1996); and enzymes for antioxidant synthesis such as GST/GPX (Roxas et al, 1997) and SOD (McKersie et al, 1999)
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.
