Plant microRNAs (miRNAs) are a particular class of small RNAs that mainly participate in gene regulation at the post-transcription level. Previous studies suggested that the balance between carbon (C) and nitrogen (N), rather than one single metabolite, affects global gene expression. Nutrient-responsive miRNAs might play crucial roles in modulating nutrient starvation responses and crosstalk among nutrient metabolic pathways. Despite genome-wide gene expression analyses, the mechanism underlying the crosstalk among C, N, and S metabolic pathways is unclear, as is the crosstalk of C/N/S with other nutrient metabolic pathways.

Prof. YU Diqiu and his team of Xishuangbanna Tropical Botanical Garden (XTBG) used deep sequencing of Arabidopsis thaliana small RNAs to reveal miRNAs that were differentially expressed in response to C, N, or S deficiency. They systemically analyzed the expression of miRNAs under C, N, or S starvation conditions.

To characterize the small RNAs responsive to C, N, or S deficiency, the researchers constructed small RNA libraries by using 10-day-old seedlings grown on full nutrient (FN), sucrose-free (–C), nitrogen-free (–N), or sulfate-free (–S) MS medium. They also compared the read counts of miRNAs under nutrient-deficient conditions with those under full nutrient, in order to explore the miRNAs that were differentially expressed in response to a specific nutrient deficiency. To investigate the functions of nutrient-responsive miRNAs in nutrient starvation adaptation, they used miRNA overexpression plants (miR160a-ox, miR395a-ox, and miR399b-ox) and miR160 suppression plants (STTM160) to evaluate phenotypes in nutrient starvation conditions.

Although a large number of miRNAs were differentially expressed in response to nutrient deficiencies, some miRNAs were specifically responsive to specific nutrient depletions. miR169b/c, miR826, and miR395 showed the largest changes in response to –C, –N, and –S, respectively. In contrast, miR167, miR172, miR397, miR398, miR399, miR408, miR775, miR827, miR841, miR857, and miR2111 are commonly suppressed by C, N, and S deficiency.

The study confirmed that a large number of miRNAs were responsive to nutrient deficiencies. Nutrient deficiency-induced miRNAs may function as signals that mediate the crosstalk between nutrient metabolic pathways.

The study entitled “Uncovering miRNAs involved in crosstalk between nutrient deficiencies in Arabidopsis” has been published in Scientific Reports.

Contact:
YU Diqiu, Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences,
Mengla, Yunnan 666303, China
Tel: 86 871 65178133
E-mail: ydq@xtbg.ac.cn