粉垄耕作对甘蔗根系生长及氮素吸收利用的调控作用

Regulation of smashing ridging tillage on sugarcane root growth and nitrogen absorption and utilization

【目的】探究粉垄耕作对甘蔗根系生长和氮素吸收利用的调控作用,为粉垄耕作技术在甘蔗生产中的推广应用提供理论依据。【方法】以甘蔗品种福农41为试验材料,以传统耕作为对照,研究粉垄耕作对甘蔗根系生物量和氮含量的影响;采用转录组测序(RNA-seq)和实时荧光定量PCR(qRT-PCR)分析粉垄耕作对甘蔗根系中氮素吸收利用相关基因表达水平的调控作用。【结果】与传统耕作相比,粉垄耕作条件下甘蔗根系鲜重、干重、氮含量分别显著增加48.7%、46.8%和50.0%(P<0.05)。RNA-seq分析结果表明,2种耕作方式的甘蔗根系存在14020个差异表达基因,其中12565个基因在粉垄耕作甘蔗根系中上调表达、1455个基因在粉垄耕作甘蔗根系中下调表达。进一步筛选到45个氮吸收利用相关的差异表达基因,包括硝酸盐转运蛋白基因、硝酸还原酶基因、亚硝酸还原酶基因、谷氨酰胺合成酶基因、谷氨酸合酶基因等,其中有44个氮吸收利用相关基因在粉垄耕作根系中上调表达。qRT-PCR分析结果显示,3个有代表性的差异表达基因TRINITYDN194141c0g1、TRINITYDN252586c0g1和TRINITYDN241177c0g1在2种耕作方式甘蔗根系中的表达差异趋势与RNA-seq分析结果一致。【结论】粉垄耕作可能通过上调甘蔗根系中氮素吸收利用相关基因表达水平来增加甘蔗根系对氮的吸收利用能力,而增加甘蔗根系中氮含量并促进根系生长;此外,由于粉垄耕作的甘蔗根系更发达,可能通过增加根系与土壤接触的总面积,进而促进甘蔗根系对土壤中氮素的吸收利用。

【Objective】In order to provide theoretical basis for the application and promotion of smashing ridging tillage in sugarcane production,the regulation of smashing ridging tillage on sugarcane root growth and nitrogen absorption and utilization was investigated.【Method】Fungong 41 sugarcane variety was selected for the experimental materials and traditional tillage was used as a control,the effects of smashing ridging tillage on sugarcane root biomass and nitrogen content were investigated;transcriptome sequencing(RNA-seq)and real-time fluorescence quantitative PCR(qRT-PCR)were used to analyze the regulation of smashing ridge tillage on the expression levels of nitrogen absorption and assimilation-related genes in sugarcane roots.【Result】Compared with the control(traditional tillage),the fresh weight,dry weight and nitrogen content of sugarcane root were significantly increased by 48.7%,46.8%and 50.0%(P<0.05),respectively.RNAseq data resulted that there were 14020 differentially expressed genes in sugarcane roots between treatments of control and smashing ridge tillage,among which 12565 genes were up-regulated and 1455 genes were down-regulated in sugarcane root of smashing ridge tillage compared with that of control.Further,45 differentially expressed genes which were related to the nitrogen absorption and utilization were screened out,including nitrate transporter genes,nitrate reductase genes,nitrite reductase genes,glutamine synthetase genes and glutamate synthase genes.Among which 44 genes were up-regulated in roots of smashing ridge tillage.qRT-PCR data displayed that the change trends of three differentially expressed genes(TRINITY_DN194141_c0_g1,TRINITY_DN252586_c0_g1,TRINITY_DN241177_c0_g1)were the same of that of the transcriptome result in root of two treatments.【Conclusion】Smashing ridging tillage may increase the capacity of nitrogen absorption and assimilation in sugarcane roots by up-regulating the expression levels of nitrogen absorption and assimilationrelated genes,thereby increasing the nitrogen content in sugarcane roots and promoting root growth.In addition,due to the more developed sugarcane roots under the treatment of smashing ridging tillage,it is possible to increase the total area of sugarcane roots to promote nitrogen absorption and utilization.