An alternative pathway to plant cold tolerance in the absence of vacuolar invertase activity. (22nd December 2022)

• Record Type: Journal Article
• Authors: Teper‐Bamnolker, Paula; Roitman, Marina; Katar, Omri; Peleg, Noam; Aruchamy, Kalaivani; Suher, Shlomit; Doron‐Faigenboim, Adi; Leibman, Diana; Omid, Ayelet; Belausov, Eduard; Andersson, Mariette; Olsson, Niklas; Fält, Ann‐Sofie; Volpin, Hanne; Hofvander, Per; Gal‐On, Amit; Eshel, Dani
• Is Part Of: Plant journal. Volume 113:Number 2(2023)
• Page Start: 327
• Page End: 341
• Publication Date: 2022-12-22
• Subjects: cold‐induced sweetening -- cold stress -- CRISPR/Cas9 -- potato -- Solanum tuberosum -- transcriptome -- vacuolar invertase; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.16049
• Languages: English
• ISSNs: 0960-7412

Abstract

SUMMARY: To cope with cold stress, plants have developed antioxidation strategies combined with osmoprotection by sugars. In potato ( Solanum tuberosum ) tubers, which are swollen stems, exposure to cold stress induces starch degradation and sucrose synthesis. Vacuolar acid invertase (VInv) activity is a significant part of the cold‐induced sweetening (CIS) response, by rapidly cleaving sucrose into hexoses and increasing osmoprotection. To discover alternative plant tissue pathways for coping with cold stress, we produced VInv‐ knockout lines in two cultivars. Genome editing of VInv in 'Désirée' and 'Brooke' was done using stable and transient expression of CRISPR/Cas9 components, respectively. After storage at 4°C, sugar analysis indicated that the knockout lines showed low levels of CIS and maintained low acid invertase activity in storage. Surprisingly, the tuber parenchyma of vinv lines exhibited significantly reduced lipid peroxidation and reduced H2 O2 levels. Furthermore, whole plants of vinv lines exposed to cold stress without irrigation showed normal vigor, in contrast to WT plants, which wilted. Transcriptome analysis of vinv lines revealed upregulation of an osmoprotectant pathway and ethylene‐related genes during cold temperature exposure. Accordingly, higher expression of antioxidant‐related genes was detected after exposure to short and long cold storage. Sugar measurements showed an elevation of an alternative pathway in the absence of VInv activity, raising the raffinose pathway with increasing levels of myo‐inositol content as a cold tolerance response. Significance Statement: Genome editing was used to discover alternative plant tissue pathways for coping with cold stress. Knockout of sucrose degradation gene increased tuber antioxidant defense and enhanced the osmoprotection pathway through the elevation of myo‐inositol levels.