Physiological and biochemical responses of transgenic potato plants with altered expression of PSII manganese stabilizing protein

• Published in: Plant physiology and biochemistry 2012-09, Vol.58, p.182-194
• Main Authors: Gururani, Mayank Anand, Upadhyaya, Chandrama Prakash, Strasser, Reto J., Woong, Yu Jae, Park, Se Won
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Carbohydrate Metabolism - genetics; Chlorophyll - metabolism; Fluorescence; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes, Plant; Oxygen - metabolism; Oxygen evolving complex; Photosynthesis - genetics; Photosystem II; Photosystem II Protein Complex - genetics; Photosystem II Protein Complex - metabolism; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Tubers - growth & development; Plants, Genetically Modified; Solanum tuberosum; Solanum tuberosum - anatomy & histology; Solanum tuberosum - metabolism; Solanum tuberosum - physiology
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2012.07.003

Manganese-stabilizing protein (MSP) represents a key component of the oxygen-evolving complex (OEC). Transgenic potato plants with both enhanced (sense) and reduced (anti-sense) MSP expression levels were generated to investigate the possible physiological role of MSP in overall plant growth, particularly in tuber development. MSP antisense plants exhibited both higher tuberization frequency and higher tuber yield with increased total soluble carbohydrates. The photosynthetic efficiencies of the plants were examined using the OJIP kinetics; MSP-antisense plants were photosynthetically more active than the MSP-sense and UT (untransformed) control plants. The oxygen measurements indicated that the relative oxygen evolution was directly proportional to the MSP expression, as MSP-antisense plants showed much lower oxygen evolution compared to MSP-sense as well as UT plants. MSP-sense plants behaved like the UT plants with respect to morphology, tuber yield, and photosynthetic performance. Chlorophyll a fluorescence analyses indicate a possible lack of intact Oxygen Evolving Complexes (OECs) in MSP antisense plants, which allow access to internal non-water electron donors (e.g., ascorbate and proline) and consequently increase the Photosystem II (PSII) activity of those plants. These findings further indicate that this altered photosynthetic machinery may be associated with early tuberization and increased tuberization frequency. ► Downregulated MSP in potato results in lack of intact oxygen evolving complex. ► Non-water electron donors get access to OEC in antisense MSP plants. ► Antisense MSP plants showed early tuberization and increased tuber yield. ► Downregulated MSP caused increased sugars, ascorbate and proline accumulation. ► First report to describe the role of MSP in any economically important crop.