Biology subjects

Garro, M.

Publications and source records attributed to Garro, M..

3 recordsLinked to original sources

bioRxiv2026

A conserved structural logic underlies sensor-helper NLR communication in the NRC immune receptor network

NLR immune receptor networks consist of expanded disease resistance proteins (sensor NLRs) that signal via core executors of immunity known as helper NLRs. Although some sensor NLRs are thought to activate their cognate helpers via an activation-and-release mechanism, the structural basis of sensor-helper communication remains poorly understood. Here, we identify and validate sensor-helper NLR interfaces that are critical for immune activation in the NRC network of coiled-coil NLR immune receptors. Using AlphaFold 3 we predicted a high confidence model between the virus resistance protein Rx and its helper NLR NRC2. We validated the interfaces by loss and gain-of-function mutagenesis, including reconstituting a critical salt bridge through reciprocal mutations. We showed that these interfaces are conserved across the NRC network of asterid plants despite over 120 million years of divergence and validated the sensor-NRC interfaces within the common lettuce network. Structure-guided bioengineering of a lettuce sensor NLR enabled expansion of its NRC helper compatibility profile. These results are consistent with the activation-and-release model and point to bioengineering sensor- helper specificity in economically important crop species.

plant biology↗

bioRxiv2026

AI-guided discovery of atypical protein assemblies

Artificial intelligence (AI) systems such as AlphaFold have transformed structural biology by enabling accurate prediction of protein structures. However, their capacity to uncover new classes of macromolecular assemblies remains largely untapped. We developed the Structural Novelty Index (SNI), a quantitative framework for identifying protein complexes that diverge from canonical architectures. As one implementation of SNI, we developed SNINRC-Hexa, to identify unconventional resistosomes formed by nucleotide-binding, leucine-rich repeat immune receptors (NLRs). We used it to analyze AlphaFold 3 models of 637 non-redundant NRC proteins from 346 genomes representing 85 plant species. This analysis identified candidates with predicted architectures distinct from the canonical hexameric resistosomes of NRC proteins. Biochemical purification and negative-stain transmission electron microscopy of NRC7 orthologs from multiple species supported the SNI prediction and revealed an unexpected undecameric (11-mer) assembly. Our results establish SNI as a scalable approach for discovering atypical protein complexes.

bioinformatics↗

bioRxiv2024

Non-CG DNA methylation modulates hypocotyl elongation during thermormorphogenesis

Plants adapt to warm environments through physiological and morphological changes termed thermomorphogenesis, which involve transcriptional reprogramming exerted mainly by PHYTOCHROME INTERACTING FACTOR 4 (PIF4). Fluctuating temperatures can also influence the patterns of cytosine DNA methylation, thereby influencing gene expression. However, whether these epigenetic changes provide an adaptative advantage remains unclear. Here, we provide evidence that DNA methylation is required to regulate thermomorphogenesis. Hypomethylated drm1 drm2 cmt3 mutants or seedlings treated with 5-azacytidine to block DNA methylation exhibit reduced hypocotyl growth at warm temperatures, primarily due to impaired cell elongation. Moreover, DNA hypomethylation compromises auxin biosynthesis and transport in response to warmth, partially by reducing PIF4 protein levels. Notably, the loss of DNA methylation leads to increased expression of SUPPRESSOR OF drm1 drm2 cmt3 (SDC), which in turn restricts hypocotyl elongation during thermomorphogenesis. Finally, we demonstrate that DNAme regulates the inhibition of SDC expression to promote gibberellin biosynthesis. Our findings underscore the critical role of DNA methylation in modulating gene expression in response to temperature fluctuations and provide new insights into the epigenetic regulation of thermomorphogenesis. HighlightsDNA methylation regulates the expression of key genes involved in auxin and gibberellin metabolism, to ensure hypocotyl growth in response to warm temperatures.

plant biology↗