Profiling of N⁶-Methyladenosine (m⁶A) Modification Landscape in Response to Drought Stress in Apple (<i>Malus prunifolia</i> (Willd.) Borkh)

Drought stress is a significant environmental factor limiting crop growth worldwide. Malus prunifolia is an important apple species endemic to China and is used for apple cultivars and rootstocks with great drought tolerance. N6-methyladenosine (m6A) is a common epigenetic modification on messenger RNAs (mRNAs) in eukaryotes which is critical for various biological processes. However, there are no reports on m6A methylation in apple response to drought stress. Here, we assessed the m6A landscape of M. prunifolia seedlings in response to drought and analyzed the association between m6A modification and transcript expression. In total, we found 19,783 and 19,609 significant m6A peaks in the control and drought treatment groups, respectively, and discovered a UGUAH (H: A/U/C) motif. In M. prunifolia, under both control and drought conditions, peaks were highly enriched in the 3′ untranslated region (UTR) and coding sequence (CDS). Among 4204 significant differential m6A peaks in drought-treated M. prunifolia compared to control-treated M. prunifolia, 4158 genes with m6A modification were identified. Interestingly, a large number of hypermethylated peaks (4069) were stimulated by drought treatment compared to hypomethylation. Among the hypermethylated peak-related genes, 972 and 1238 differentially expressed genes (DEGs) were up- and down-regulated in response to drought, respectively. Gene ontology (GO) analyses of differential m6A-modified genes revealed that GO slims related to RNA processing, epigenetic regulation, and stress tolerance were significantly enriched. The m6A modification landscape depicted in this study sheds light on the epigenetic regulation of M. prunifolia in response to drought stress and indicates new directions for the breeding of drought-tolerant apple trees

Transcriptional Effects of Rootstock on Scion after Drought: A Case Study of Using <i>MdGH3</i> RNAi as the Rootstock

Drought stress is an important environmental factor limiting apple yield and fruit quality. Previously, we identified GRETCHEN HAGEN3.6 (GH3.6) as a negative regulator of drought stress in apple trees. Using transgenic MdGH3 RNAi (knocking down MdGH3.6 and its five homologs) plants as rootstock can increase drought tolerance, water use efficiency, flowering, and fruit quality of the Fuji scion after drought stress. However, the molecular mechanism behind this phenomenon is still unknown. Here, we performed transcriptome sequencing of the grafted plants (Fuji/GL-3 where Fuji was used as the scion and non-transgenic GL-3 was used as the rootstock, and Fuji/MdGH3 RNAi where MdGH3 RNAi was used as the rootstock) under control and drought conditions. Under control conditions, 667 up-regulated genes and 176 down-regulated genes were identified in the scion of Fuji/MdGH3 RNAi, as compared to the scion of Fuji/GL-3. Moreover, 941 up-regulated genes and 2226 down-regulated genes were identified in the rootstock of MdGH3 RNAi plants relative to GL-3. GO terms of these differentially expressed genes (DEGs) in scion and rootstock showed associations with plant growth, fruit development, and stress responses. After drought stress, 220 up-regulated and 452 down-regulated genes were identified in MdGH3 RNAi rootstock, as compared to GL-3. Significantly enriched GO terms included response to abiotic stimulus, cell division, microtubule-based process, metabolic and biosynthetic process of flavonoid, pigment, and lignin. The comparison between the scion of Fuji/MdGH3 RNAi and Fuji/GL-3 yielded a smaller number of DEGs; however, all of them were significantly enriched in stress-related GO terms. Furthermore, 365 and 300 mRNAs could potentially move from MdGH3 RNAi rootstock to scion under control and drought conditions, respectively, including FIDDLEHEAD (FDH), RESPONSIVE TO DESICCATION 26 (RD26), ARS-binding factor 2 (ABF2), WRKY75, and ferritin (FER). Overall, our work demonstrates the effects of rootstock on scion at the transcriptional level after drought stress and provides theoretical support for further understanding and utilization of MdGH3 RNAi plants

Magnetoelectric Sensor Operating in <i>d</i>₁₅ Thickness-Shear Mode for High-Frequency Current Detection

For the application of high-frequency current detection in power systems, such as very fast transient current, lightning current, partial discharge pulse current, etc., current sensors with a quick response are indispensable. Here, we propose a high-frequency magnetoelectric current sensor, which consists of a PZT piezoelectric ceramic and Metglas amorphous alloy. The proposed sensor is designed to work under d15 thickness-shear mode, with the resonant frequency around 1.029 MHz. Furthermore, the proposed sensor is fabricated as a high-frequency magnetoelectric current sensor. A comparative experiment is carried out between the tunnel magnetoresistance sensor and the magnetoelectric sensor, in the aspect of high-frequency current detection up to 3 MHz. Our experimental results demonstrate that the d15 thickness-shear mode magnetoelectric sensor has great potential for high-frequency current detection in smart grids

A chromosome-scale reference genome provides insights into the genetic origin and grafting-mediated stress tolerance of Malus prunifolia

27openInternationalInternational coauthor/editoropenLi, Z.; Wang, L.; He, J.; Li, X.; Hou, N.; Guo, J.; Niu, C.; Li, C.; Liu, S.; Xu, J.; Xie, Y.; Zhang, D.; Shen, X.; Lu, L.; Gend, D.; Chen, P.; Jiang, L.; Wang, L.; Li, H.; Malnoy, M.; Deng, C.; Zou, Y.; Li, C.; Zhan, X.; Ma, F.; Zu, Q.; Guan, Q.Li, M.; Wang, L.; He, J.; Li, X.; Hou, N.; Guo, J.; Niu, C.; Li, C.; Liu, S.; Xu, J.; Xie, Y.; Zhang, D.; Shen, X.; Lu, L.; Gend, D.; Chen, P.; Jiang, L.; Wang, L.; Li, H.; Malnoy, M.; Deng, C.; Zou, Y.; Li, C.; Zhan, X.; Ma, F.; Zu, Q.; Guan, Q