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Sriskantharajah K, El Kayal W, Torkamaneh D, Ayyanath MM, Saxena PK, Sullivan AJ, Paliyath G, Subramanian J. Transcriptomics of Improved Fruit Retention by Hexanal in 'Honeycrisp' Reveals Hormonal Crosstalk and Reduced Cell Wall Degradation in the Fruit Abscission Zone. Int J Mol Sci 2021; 22:ijms22168830. [PMID: 34445535 PMCID: PMC8396267 DOI: 10.3390/ijms22168830] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 08/09/2021] [Accepted: 08/13/2021] [Indexed: 12/13/2022] Open
Abstract
Apples (Malus domestica Borkh) are prone to preharvest fruit drop, which is more pronounced in 'Honeycrisp'. Hexanal is known to improve fruit retention in several economically important crops. The effects of hexanal on the fruit retention of 'Honeycrisp' apples were assessed using physiological, biochemical, and transcriptomic approaches. Fruit retention and fruit firmness were significantly improved by hexanal, while sugars and fresh weight did not show a significant change in response to hexanal treatment. At commercial maturity, abscisic acid and melatonin levels were significantly lower in the treated fruit abscission zone (FAZ) compared to control. At this stage, a total of 726 differentially expressed genes (DEGs) were identified between treated and control FAZ. Functional classification of the DEGs showed that hexanal downregulated ethylene biosynthesis genes, such as S-adenosylmethionine synthase (SAM2) and 1-aminocyclopropane-1-carboxylic acid oxidases (ACO3, ACO4, and ACO4-like), while it upregulated the receptor genes ETR2 and ERS1. Genes related to ABA biosynthesis (FDPS and CLE25) were also downregulated. On the contrary, key genes involved in gibberellic acid biosynthesis (GA20OX-like and KO) were upregulated. Further, hexanal downregulated the expression of genes related to cell wall degrading enzymes, such as polygalacturonase (PG1), glucanases (endo-β-1,4-glucanase), and expansins (EXPA1-like, EXPA6, EXPA8, EXPA10-like, EXPA16-like). Our findings reveal that hexanal reduced the sensitivity of FAZ cells to ethylene and ABA. Simultaneously, hexanal maintained the cell wall integrity of FAZ cells by regulating genes involved in cell wall modifications. Thus, delayed fruit abscission by hexanal is most likely achieved by minimizing ABA through an ethylene-dependent mechanism.
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Affiliation(s)
- Karthika Sriskantharajah
- Department of Plant Agriculture, University of Guelph, 50 Stone Road E, Guelph, ON N1G2W1, Canada; (K.S.); (D.T.); (M.M.A.); (P.K.S.); (A.J.S.); (G.P.)
| | - Walid El Kayal
- Department of Plant Agriculture, University of Guelph-Vineland Station, 4890 Victoria Ave N, Vineland, ON L0R2E0, Canada;
- Faculty of Agricultural and Food Science, American University of Beirut, Riad El Solh, P.O. Box 11-0236, Beirut 1107 2020, Lebanon
| | - Davoud Torkamaneh
- Department of Plant Agriculture, University of Guelph, 50 Stone Road E, Guelph, ON N1G2W1, Canada; (K.S.); (D.T.); (M.M.A.); (P.K.S.); (A.J.S.); (G.P.)
- Faculté des Sciences de l’Agriculture et de l’alimentation, Universite Laval, Pavillon Paul-Comtois, 2425, rue de l’Agriculture, Local 1122, Québec City, QC G1V 0A6, Canada
| | - Murali M. Ayyanath
- Department of Plant Agriculture, University of Guelph, 50 Stone Road E, Guelph, ON N1G2W1, Canada; (K.S.); (D.T.); (M.M.A.); (P.K.S.); (A.J.S.); (G.P.)
| | - Praveen K. Saxena
- Department of Plant Agriculture, University of Guelph, 50 Stone Road E, Guelph, ON N1G2W1, Canada; (K.S.); (D.T.); (M.M.A.); (P.K.S.); (A.J.S.); (G.P.)
| | - Alan J. Sullivan
- Department of Plant Agriculture, University of Guelph, 50 Stone Road E, Guelph, ON N1G2W1, Canada; (K.S.); (D.T.); (M.M.A.); (P.K.S.); (A.J.S.); (G.P.)
| | - Gopinadhan Paliyath
- Department of Plant Agriculture, University of Guelph, 50 Stone Road E, Guelph, ON N1G2W1, Canada; (K.S.); (D.T.); (M.M.A.); (P.K.S.); (A.J.S.); (G.P.)
| | - Jayasankar Subramanian
- Department of Plant Agriculture, University of Guelph-Vineland Station, 4890 Victoria Ave N, Vineland, ON L0R2E0, Canada;
- Correspondence: ; Tel.: +1-905-562-4141 (ext. 134)
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Hezema YS, Shukla MR, Goel A, Ayyanath MM, Sherif SM, Saxena PK. Rootstocks Overexpressing StNPR1 and StDREB1 Improve Osmotic Stress Tolerance of Wild-Type Scion in Transgrafted Tobacco Plants. Int J Mol Sci 2021; 22:8398. [PMID: 34445105 PMCID: PMC8395105 DOI: 10.3390/ijms22168398] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 12/24/2022] Open
Abstract
In grafted plants, the movement of long-distance signals from rootstocks can modulate the development and function of the scion. To understand the mechanisms by which tolerant rootstocks improve scion responses to osmotic stress (OS) conditions, mRNA transport of osmotic responsive genes (ORGs) was evaluated in a tomato/potato heterograft system. In this system, Solanum tuberosum was used as a rootstock and Solanum lycopersicum as a scion. We detected changes in the gene expression levels of 13 out of the 21 ORGs tested in the osmotically stressed plants; of these, only NPR1 transcripts were transported across the graft union under both normal and OS conditions. Importantly, OS increased the abundance of StNPR1 transcripts in the tomato scion. To examine mRNA mobility in transgrafted plants, StNPR1 and StDREB1 genes representing the mobile and non-mobile transcripts, respectively, were overexpressed in tobacco (Nicotiana tabacum). The evaluation of transgenic tobacco plants indicated that overexpression of these genes enhanced the growth and improved the physiological status of transgenic plants growing under OS conditions induced by NaCl, mannitol and polyethylene glycol (PEG). We also found that transgenic tobacco rootstocks increased the OS tolerance of the WT-scion. Indeed, WT scions on transgenic rootstocks had higher ORGs transcript levels than their counterparts on non-transgenic rootstocks. However, neither StNPR1 nor StDREB1 transcripts were transported from the transgenic rootstock to the wild-type (WT) tobacco scion, suggesting that other long-distance signals downstream these transgenes could have moved across the graft union leading to OS tolerance. Overall, our results signify the importance of StNPR1 and StDREB1 as two anticipated candidates for the development of stress-resilient crops through transgrafting technology.
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Affiliation(s)
- Yasmine S. Hezema
- Gosling Research Institute for Plant Preservation, Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada; (Y.S.H.); (M.R.S.); (A.G.); (M.M.A.)
- Department of Horticulture, Damanhour University, Damanhour 22713, El-Beheira, Egypt
| | - Mukund R. Shukla
- Gosling Research Institute for Plant Preservation, Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada; (Y.S.H.); (M.R.S.); (A.G.); (M.M.A.)
| | - Alok Goel
- Gosling Research Institute for Plant Preservation, Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada; (Y.S.H.); (M.R.S.); (A.G.); (M.M.A.)
| | - Murali M. Ayyanath
- Gosling Research Institute for Plant Preservation, Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada; (Y.S.H.); (M.R.S.); (A.G.); (M.M.A.)
| | - Sherif M. Sherif
- Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Tech, Winchester, VA 22602, USA
| | - Praveen K. Saxena
- Gosling Research Institute for Plant Preservation, Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada; (Y.S.H.); (M.R.S.); (A.G.); (M.M.A.)
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