<institution content-type="university">Department of Biochemistry and Molecular Biology, Federal University of Paraná</institution>, <city>Curitiba</city>, <state>Paraná</state>, <country>Brazil</country>.
<institution content-type="university">Department of Botany, Institute of Biosciences, University of São Paulo</institution>, <city>São Paulo</city>, <country>Brazil</country>.
Funct Plant Biol. 2023 Dec;50(12):1010-1027. doi: 10.1071/FP22272.
Araucaria angustifolia is a critically endangered species and its distribution can be affected by an increase in temperature. In this study, we evaluated the effects of heat stress (30°C) on Araucaria angustifolia cell lines responsive (SE1) and non-responsive (SE6) to the development of somatic embryos. The viability of both cell lines was reduced by heat stress and mitochondria were the organelles most affected. Heat stress for 24h increased the reactive oxygen species (ROS) levels in SE1 cells, followed by a reduction at 48 and 72h. In SE6 cells, an increase occurred after 24 and 48h of stress, returning to control levels at 72h. H2 O2 levels were increased after 24h for both SE1 and SE6 cells, being higher for SE6. Interestingly, at 48 and 72h, H2 O2 levels decreased in SE1 cells, while in SE6, the values returned to the control levels. The respiration of SE6 cells in the presence of oxidisable substrates was inhibited by heat stress, in agreement with the high lipid peroxidation levels. The AaSERK1 gene was identified in both cultures, with greater expression in the SE1 line. Heat stress for 24 and 48h increased gene expression only in this cell line. The activity of peroxidase, superoxide dismutase and enzymes of the glutathione/ascorbate cycle was increased in both cell lines subjected to heat stress. Catalase activity was increased only in SE6 cells at 72h of exposure. These results show that responsive SE1 cells can modulate ROS levels more efficiently than SE6 when these cells are stressed by heat. This ability may be related to the maturation capacity of these cells.
南洋杉是一种濒危物种，其分布可能会受到温度升高的影响。本研究评估了热应激（30°C）对南洋杉响应（SE1）和非响应（SE6）体细胞胚发生的细胞系的影响。两种细胞系的活力均因热应激而降低，其中线粒体受影响最大。SE1 细胞在热应激 24h 后活性氧（ROS）水平增加，随后在 48 和 72h 时降低。SE6 细胞在应激 24 和 48h 后ROS 水平增加，在 72h 时恢复到对照水平。SE1 和 SE6 细胞在 24h 后 H2O2 水平升高，SE6 细胞更高。有趣的是，在 48 和 72h，SE1 细胞中的 H2O2 水平下降，而 SE6 细胞中的值恢复到对照水平。在存在可氧化底物的情况下，SE6 细胞的呼吸受到热应激的抑制，这与高水平的脂质过氧化水平一致。在两种培养物中都鉴定出 AaSERK1 基因，SE1 系中的表达更高。SE1 系中的基因表达仅在热应激 24 和 48h 时增加。两种细胞系的过氧化物酶、超氧化物歧化酶和谷胱甘肽/抗坏血酸循环中的酶的活性在受到热应激时均增加。仅在 SE6 细胞在暴露 72h 时增加了过氧化氢酶的活性。这些结果表明，在受到热应激时，响应型 SE1 细胞可以比 SE6 细胞更有效地调节 ROS 水平。这种能力可能与这些细胞的成熟能力有关。
