Table_1_Physiological and Molecular Changes in Cherry Red Tobacco in Response to Iron Deficiency Stress.docx

The genotype CR60 is a spontaneous Cherry Red variant (containing granular red dapples on flue-cured leaves) of the Yunyan 87 (Y87) tobacco; it accumulates higher concentration of iron (Fe) in leaves than Y87, but the physiological differences between them remain largely unknown. We investigated the physiological and molecular mechanisms of CR60 in response to Fe deficiency under hydroponic conditions. Our results showed no significant phenotypic difference between Y87 and CR60 at optimal (40 μM) and high Fe (160 and 320 μM) concentrations. By contrast, CR60 exhibited higher tolerance to Fe deficiency (0 μM) than Y87, as shown by higher concentrations of chlorophyll in CR60 leaves after 21-day Fe-deficiency stress. Transcriptome profiling coupled with RT-PCR analyses found that the expression of IRT1 and several genes associated with chlorophyll biosynthesis and photosynthesis (e.g., PRO, GSA, FD1, PsbO, and PC) was higher in CR60 than Y87. These results indicated that CR60 maintains sufficient Fe uptake, chlorophyll biosynthesis and photosynthetic rate when subjected to Fe starvation.

CR60基因型为一种自发的樱桃红变异品种（叶片上含有颗粒状红斑点的烤烟品种Yunyan 87，简称Y87），相较于Y87，其叶片中铁（Fe）的积累浓度更高，然而，两者间的生理差异却鲜有研究。本研究旨在探究CR60在营养液栽培条件下对铁缺乏的生理和分子机制。研究发现，在最佳铁浓度（40 μM）和高铁浓度（160和320 μM）下，Y87与CR60在表型上并无显著差异。然而，与Y87相比，CR60在铁缺乏（0 μM）条件下表现出更高的耐受性，这在21天铁缺乏胁迫后CR60叶片中较高的叶绿素浓度中得到体现。转录组分析结合RT-PCR技术发现，与Y87相比，CR60中IRT1以及与叶绿素生物合成和光合作用相关的多个基因（如PRO、GSA、FD1、PsbO和PC）的表达水平更高。这些结果表明，当CR60受到铁饥饿时，仍能维持足够的铁吸收、叶绿素生物合成和光合速率。