RNA sequencing and functional analysis uncover key long non-coding RNAs involved in regulating pollen fertility...

Gametocidal (Gc) chromosomes have been widely utilized in genetic breeding due to their ability to induce chromosomal breakage and eliminate gametes that lack them. Long noncoding RNAs (lncRNAs) have various functional mechanisms in regulating pollen and anther development; however, their regulatory contributions to Gc action are still unknown. Here, we identified 2824 differentially expressed lncRNAs (DE-lncRNAs) from the anther tissues of Triticum aestivum cv. Chinese Spring (CS) and Chinese Spring-Gc 3C chromosome monosomic addition line (CS-3C) through sequencing. In this study, we predicted 161 target mRNAs for 145 DE-lncRNAs, including 104 cis-regulatory, 60 trans-regulatory, and three both cis-regulatory and trans-regulatory manner. Combined with our previous miRNA sequencing data, 241 DE-lncRNAs functioned as potential endogenous target mimics (eTMs) for 84 differentially expressed microRNAs (DE-miRNAs, including 12 novel miRNAs). The results of transient transformation in tobacco leaves indicated that L006278 could bind to MTCONS_00006277, which encoded a calcineurin CBL-interacting protein kinase 19-like, and suppress its expression. Furthermore, L117735 could function as an eTM for tae-miR9657b-3p, and L056972 could function as an eTM for gc-m2240-5p. To explore the function of lncRNAs in the process of Gc action, we transformed L006278, an up-regulated lncRNA in CS-3C, into rice to analyze its effect on pollen fertility. Overexpression of L006278 led to a reduction in rice pollen fertility. Overall, our findings indicate that lncRNAs can contribute to the regulation of pollen fertility during the process of Gc action by regulating the expression levels of target mRNAs and acting as eTMs for certain key miRNAs.