School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.
Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, Hunan Agricultural University, Changsha 410128, China.
J Integr Plant Biol. 2019 Apr;61(4):449-462. doi: 10.1111/jipb.12716. Epub 2018 Nov 26.
The rhizosheath, a layer of soil particles that adheres firmly to the root surface by a combination of root hairs and mucilage, may improve tolerance to drought stress. Setaria italica (L.) P. Beauv. (foxtail millet), a member of the Poaceae family, is an important food and fodder crop in arid regions and forms a larger rhizosheath under drought conditions. Rhizosheath formation under drought conditions has been studied, but the regulation of root hair growth and rhizosheath size in response to soil moisture remains unclear. To address this question, in this study we monitored root hair growth and rhizosheath development in response to a gradual decline in soil moisture. Here, we determined that a soil moisture level of 10%-14% (w/w) stimulated greater rhizosheath production compared to other soil moisture levels. Root hair density and length also increased at this soil moisture level, which was validated by measurement of the expression of root hair-related genes. These findings contribute to our understanding of rhizosheath formation in response to soil water stress.
根鞘是一层土壤颗粒，通过根毛和黏液的结合牢固地附着在根表面，它可能提高植物对干旱胁迫的耐受能力。黍属（Setaria italica (L.) P. Beauv.）是禾本科的一个成员，是干旱地区重要的粮食和饲料作物，在干旱条件下形成更大的根鞘。已经研究了干旱条件下根鞘的形成，但对根毛生长和根鞘大小对土壤水分的响应调节仍不清楚。为了解决这个问题，本研究监测了土壤水分逐渐下降时根毛生长和根鞘发育的情况。在这里，我们确定土壤水分水平为 10%-14%（w/w）比其他土壤水分水平更能刺激根鞘的产生。在这个土壤水分水平下，根毛密度和长度也增加了，这通过测量与根毛相关的基因的表达得到了验证。这些发现有助于我们理解根鞘对土壤水分胁迫的响应。
