Root-Suppressed Phenotype of Tomato Rs Mutant is Seemingly Related to Expression of Root-Meristem-Specific Sulfotransferases
Authors: Kumari, A., Gupta, P., Santisree, P., Pamei, I., Valluri,, S., Sharma, K., Venkateswara Rao, K., Shukla, S., Nama, S., Sreelakshmi, Y., Sharma, R.
The study characterizes a radiation‑induced root‑suppressed (Rs) mutant in tomato that displays dwarfism and pleiotropic defects in leaves, flowers, and fruits. Metabolite profiling and rescue with H2S donors implicate disrupted sulfur metabolism, and whole‑genome sequencing identifies promoter mutations in two root‑meristem‑specific sulfotransferase genes as likely contributors to the root phenotype.
The study demonstrates that Magnesium Iron-layered double hydroxide (MgFe-LDH) nanocarriers effectively protect and deliver fungal effector dsRNA to pea leaves, enabling sustained gene silencing of Erysiphe pisi and providing enhanced local and systemic powdery mildew resistance for up to 15 days. The LDH formulation exhibits strong leaf adherence, biocompatibility, RNase protection, and rapid uptake into plant cells and fungal haustoria, outperforming dsRNA or LDH alone.
An ancient alkalinization factor informs Arabidopsis root development
Authors: Xhelilaj, K., von Arx, M., Biermann, D., Parvanov, A., Faiss, N., Monte, I., Klingelhuber, F., Zipfel, C., Timmermans, M., Oecking, C., Gronnier, J.
The study identifies members of the REMORIN protein family as inhibitors of plasma membrane H⁺‑ATPases, leading to extracellular pH alkalinization that modulates cell surface processes such as steroid hormone signaling and coordinates root developmental transitions in Arabidopsis thaliana. This inhibition represents an ancient mechanism predating root evolution, suggesting that extracellular pH patterning has shaped plant morphogenesis.
The authors used a bottom‑up thermodynamic modelling framework to investigate how plants decode calcium signals, starting from Ca2+ binding to EF‑hand proteins and extending to higher‑order decoding modules. They identified six universal Ca2+-decoding modules that can explain variations in calcium sensitivity among kinases and provide a theoretical basis for interpreting calcium signal amplitude and frequency in plant cells.
AGO5 restricts virus vertical transmission in plant gametophytes
Authors: Hoffmann, G., Sadhu, S. P., Bradamante, G., Diez Marulanda, J. C., Proschwitz, A., Wegscheider, T., Turhan, I., Bente, H., Gutzat, R., Incarbone, M.
The study demonstrates that the RNAi factor AGO5, expressed in Arabidopsis thaliana shoot apical meristem stem cells and germline, markedly reduces vertical transmission of Turnip yellow mosaic virus (TYMV). Using controlled pollination with ago5 knock‑out and cell type‑specific rescue lines, the authors show that AGO5 functions in pollen and sperm cells to block virus passage, and that targeted activation of antiviral RNAi in sperm further lowers transmission rates.
The study identified lineage-specific long non‑coding RNAs (lncRNAs) from the aphid‑specific Ya gene family in Rhopalosiphum maidis and R. padi, demonstrating that these Ya lncRNAs are secreted into maize, remain stable, and move systemically. RNA interference of Ya genes reduced aphid fecundity, while ectopic expression of Ya lncRNAs in maize enhanced aphid colonization, indicating that Ya lncRNAs act as cross‑kingdom effectors that influence aphid virulence.
The study characterizes insertion mutants of the Arabidopsis thaliana CKL12 kinase, revealing its role in hypocotyl and primary root growth and indicating that the 3' end of its transcript is crucial for function. Evidence suggests CKL12 is transcriptionally regulated by brassinosteroid signaling, as its promoter binds BR-related transcription factors and their RNAi-mediated knock‑down reduces CKL12 expression, placing CKL12 downstream of BR signaling in seedling development.
The study identifies the brown planthopper salivary protein NlAnnexin-like5 (NlANX5) as a key virulence effector that disrupts rice annexin (OsANN) function, leading to altered calcium signaling and reduced plant resistance. RNAi silencing of NlANX5 impairs BPH feeding, while transgenic rice overexpressing OsANN2/OsANN8 or NlANX5 restores resistance, demonstrating an anti‑virulence breeding strategy for rice.
The study profiled root transcriptomes of Arabidopsis wild type and etr1 gain-of-function (etr1-3) and loss-of-function (etr1-7) mutants under ethylene or ACC treatment, identifying 4,522 ethylene‑responsive transcripts, including 553 that depend on ETR1 activity. ETR1‑dependent genes encompassed ethylene biosynthesis enzymes (ACO2, ACO3) and transcription factors, whose expression was further examined in an ein3eil1 background, revealing that both ETR1 and EIN3/EIL1 pathways regulate parts of the network controlling root hair proliferation and lateral root formation.
The study introduces a minimal precursor platform for synthetic trans-acting siRNAs (syn-tasiRNAs) in tomato, leveraging the endogenous SlmiR482b microRNA to produce functional silencing agents in both transgenic and virus-induced gene silencing (VIGS) systems. Minimal precursors successfully silenced endogenous genes and conferred resistance to tomato spotted wilt virus, and a transgene‑free delivery via crude extracts was demonstrated, highlighting a versatile tool for precision RNAi in Solanum lycopersicum.