Stachyose triggers apoptotic like cell death in drought sensitive but not resilient plants

Abstract

Programmed cell death (PCD) is one of the most intensively researched fields in modern mammalian biology with roles in cancer, aging, diabetes and numerous neurodegenerative diseases. It is becoming increasingly clear that PCD also plays significant roles in plant defence and responses to the environment. Given their unique ability to tolerate desiccation (cells remain viable even after they’ve lost 95% of their water), resurrection plants make ideal models to study the regulation of plant PCD pathways. Previously, we showed that the Australian resurrection plant, Tripogon loliiformis, suppresses plant PCD, via trehalose-mediated activation of autophagy pathways, during drying. In the present study, we created a full-length T. loliiformis cDNA library, performed a large-scale Agrobacterium screen for improved salinity tolerance and identified Stachyose synthase (TlStach) as a potential candidate for improving stress tolerance. Tripogon loliiformis shoots accumulate stachyose synthase transcripts and stachyose during drying. Attempts to generate transgenic plants expressing TlStach failed and were consistent with previous reports in mammals that demonstrated stachyose-mediated induction of apoptosis. Using a combination of transcriptomics, metabolomics and cell death assays (TUNNEL and DNA laddering), we investigated whether stachyose induces apoptotic-like cell death in T. loliiformis. We show that stachyose triggers the formation of the hallmarks of plant apoptotic-like cell death in the desiccation sensitive Nicotiana benthamiana but not the resilient T. loliiformis. These findings suggest that T. loliiformis suppresses stachyose-mediated apoptotic-like cell death and provides insights on the role of sugar metabolism and plant PCD pathways. A better understanding of how resilient plants regulate sugar metabolism and PCD pathways may facilitate future targeting of plant metabolic pathways for increased stress tolerance.

Transmembrane potential, an indicator in situ reporting cellular senescence and stress response in plant tissues

“…5 D). A number of stresses including salinity [ 67 , 90 ], osmosis [ 68 ], drought [ 67 , 69 ], toxic metals [ 70 , 71 ], high temperature [ 61 , 72 ] and frost [ 73 ] can lead to premature senescence and even apoptosis in plants. To observe whether the TMP of plant tissues would be depolarized and report the earlier senescence signal after stress stimuli, in contrast to the expectations, the TMP of Arabidopsis rosette leaves under hypertonic environment was hyperpolarized instead of depolarized (Fig.…”

Insights from a Multi-Omics Integration (MOI) Study in Oil Palm (Elaeis guineensis Jacq.) Response to Abiotic Stresses: Part Two—Drought

“…This enzyme catalyzes the reaction that produces myo-inositol plus stachyose from alpha-D-Galactosyl-(1->3)-1D-myo-inositol and Raffinose and was regulated positively in the drought-tolerant conifer Larix olgensis A. Henry under PEG-simulated drought stress [ 35 ]. According to Okemo et al [ 36 ], the shoots of Tripogon loliiformis —an Australian resurrection plant—accumulated stachyose synthase transcripts and stachyose during drought stress. Stachyose triggers the formation of the hallmarks of plant apoptotic-like cell death in the desiccation-sensitive Nicotiana benthamiana but not the resilient T. loliiformis .…”

Potential Biotechnological Applications of Autophagy for Agriculture

“…Autophagy’s efficient degradation of select proteins and large aggregates or organelles facilitates tolerance against severe stress states, such as desiccation ( Williams et al, 2015 ; Oliver et al, 2020 ). Recent studies demonstrate that the native Australian resurrection grass, Tripogon loliiformis , uses trehalose metabolism to promote and maintain autophagy pathways that prevent senescence and PCD ( Williams et al, 2015 ; Asami et al, 2019 ; Okemo et al, 2021 ). A similar role for autophagy in desiccation tolerance occurs for the resurrection plant, Boea hygrometrica ( Zhu et al, 2015 ).…”