Alleviatory effects of silicon on the foliar micromorphology and anatomy of rice (Oryza sativa L.) seedlings under simulated acid rain

LncRNA TCONS_00021861 is functionally associated with drought tolerance in rice (Oryza sativa L.) via competing endogenous RNA regulation

BACKGROUND

Water deficit is an abiotic stress that retards plant growth and destabilizes crop production. Long non coding RNAs (lncRNAs) are a class of non-coding endogenous RNAs that participate in diverse cellular processes and stress responses in plants. lncRNAs could function as competing endogenous RNAs (ceRNA) and represent a novel layer of gene regulation. However, the regulatory mechanism of lncRNAs as ceRNA in drought stress response is yet unclear.

RESULTS

In this study, we performed transcriptome-wide identification of drought-responsive lncRNAs in rice. Thereafter, we constructed a lncRNA-mediated ceRNA network by analyzing competing relationships between mRNAs and lncRNAs based on ceRNA hypothesis. A drought responsive ceRNA network with 40 lncRNAs, 23 miRNAs and 103 mRNAs was obtained. Network analysis revealed TCONS_00021861/miR528-3p/YUCCA7 regulatory axis as a hub involved in drought response. The miRNA-target expression and interaction were validated by RT-qPCR and RLM-5'RACE. TCONS_00021861 showed significant positive correlation (r = 0.7102) with YUCCA7 and negative correlation with miR528-3p (r = -0.7483). Overexpression of TCONS_00021861 attenuated the repression of miR528-3p on YUCCA7, leading to increased IAA (Indole-3-acetic acid) content and auxin overproduction phenotypes.

CONCLUSIONS

TCONS_00021861 could regulate YUCCA7 by sponging miR528-3p, which in turn activates IAA biosynthetic pathway and confer resistance to drought stress. Our findings provide a new perspective of the regulatory roles of lncRNAs as ceRNAs in drought resistance of rice.

The Effects of Silicon and Different Types of Acid Rain on Root Growth and Physiology Activity of Oryza Sativa L. Seedlings

The effect of silicon (Si) and different types of acid rain (AR) on rice seedling roots was elucidated. The results showed different types of AR had different effects. Nitrate AR at pH 3.0 could promote the growth of rice roots, increased the dry weight, improved root phenotype, boosted H₂O₂ contents and increased peroxidase, catalase and ascorbate peroxidase activities. Sulfate AR at pH 3.0 could significantly inhibit the growth of rice roots, decreased the dry weight, root phenotype, increased H₂O₂ content and autioxidant enzyme activities. Sulfate-nitrate AR at pH 3.0 spraying had no significant effect on rice roots. Under different types of AR stress, the addition of exogenous Si could significantly promote the growth of rice seedling roots. This results indicated that the effects of rice root caused by AR might be due to not only the types of AR but also the content of Si in soil.