Kimura Yuki, Ushiwatari Tsukasa, Suyama Akiko, Tominaga-Wada Rumi, Wada Takuji, Maruyama-Nakashita Akiko
Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Graduate School of Biosphere Sciences, Hiroshima University, 1-4-4 Kagamiyama, Higashi Hiroshima, Hiroshima 739-8528, Japan.
Plants (Basel). 2019 Apr 19;8(4):106. doi: 10.3390/plants8040106.
Root hairs often contribute to nutrient uptake from environments, but the contribution varies among nutrients. In , two high-affinity sulfate transporters, SULTR1;1 and SULTR1;2, are responsible for sulfate uptake by roots. Their increased expression under sulfur deficiency (-S) stimulates sulfate uptake. Inspired by the higher and lower expression, respectively, of in mutants with more ( []) and fewer ( []) root hairs, we examined the contribution of root hairs to sulfate uptake. Sulfate uptake rates were similar among plant lines under both sulfur sufficiency (+S) and -S. Under -S, the expression of and was negatively correlated with the number of root hairs. These results suggest that both -S-induced expression and sulfate uptake rates were independent of the number of root hairs. In addition, we observed (1) a negative correlation between primary root lengths and number of root hairs and (2) a greater number of root hairs under -S than under +S. These observations suggested that under both +S and -S, sulfate uptake was influenced by the root biomass rather than the number of root hairs.
根毛通常有助于从环境中吸收养分，但不同养分的吸收情况有所不同。在植物中，两个高亲和力硫酸盐转运蛋白SULTR1;1和SULTR1;2负责根系对硫酸盐的吸收。它们在缺硫（-S）条件下表达增加，从而刺激硫酸盐吸收。分别受根毛较多（[突变体1]）和根毛较少（[突变体2]）的突变体中二者较高和较低表达的启发，我们研究了根毛对硫酸盐吸收的贡献。在硫充足（+S）和缺硫（-S）条件下，不同植株系之间的硫酸盐吸收速率相似。在缺硫条件下，SULTR1;1和SULTR1;2的表达与根毛数量呈负相关。这些结果表明，缺硫诱导的SULTR1;1和SULTR1;2表达以及硫酸盐吸收速率均与根毛数量无关。此外，我们观察到：（1）主根长度与根毛数量呈负相关；（2）缺硫条件下的根毛数量多于硫充足条件下的根毛数量。这些观察结果表明，在硫充足和缺硫条件下，硫酸盐吸收均受根系生物量的影响，而非根毛数量的影响。
