Plant Genomes in a Changing Environment (III)

Hi, this is my account of the first few talks from the last day of the meeting.

Claudia Köhler, Swedish University of Agricultural Sciences, Sweden

She talks about imprinted genes which are flanked by transposable elements (TE) in Arabidopsis thaliana. They find that RNApolIV mutants suppress triploid seed abortions. RNApolIV is know to be involved in RNA-guided methylation. They found that RNApolIV is behind the biogenesis of easiRNAs from TEs, and that correlates with decreased CHH methylation in the endosperm of triploid seeds (https://www.ncbi.nlm.nih.gov/pubmed/29335544). So they propose that pollen-derived easiRNAs are functional after fertilization and have a transgenerational role in assessing gamete compatibility, similar to animal piRNAs. The relevance of the results is that these mechanisms allow rapid evolution of hybridization barriers and ultimately speciation.

Isabel Bäurle, University of Potsdam, Germany

She talks about how Arabidopsis thaliana plants remember past stress events, particular heat, which is one of the most fluctuating stress sources in nature. She describes Heat Shock Factor 2 (HSFA2) and how it associates transiently to genes conferring heat memory. Target genes were observed to accumulate H3K4me3, making chromatin accessible for at least 5 days  (https://www.ncbi.nlm.nih.gov/pubmed/26657708, http://www.plantcell.org/content/early/2014/04/25/tpc.114.123851). Then she moves to describing BRU1/TSK/MGO3, which is orthologous to animal TSL, which has an epigenetic role during DNA replication and is also required for heat memory ensuring that chromatin marks are inherited during cell division (https://onlinelibrary.wiley.com/doi/abs/10.1111/pce.13365). Their long-term goal is to provide stress-memory to crops in the right moment so that yield is not too affected.

Manu Dubin, CNRS / Université de Lille, France

He explains he is back to academia from industry and that he is studying how both climate of origin and breeding efforts influence DNA methylation in barley (Hordeum vulgare) and how that is linked to adaptation, inspired in previous work on climate clines in A. thaliana. They used USDA barley core collection (inbred seeds from Mexico) with both landraces and cultivars from Europe and North America, but does not include any Iberian barleys nor North-African, which are known to contribute to the genetic diversity of the species (see for instance https://link.springer.com/article/10.1007/s11032-018-0816-z). They observe that winter barleys have slightly higher CG methylation than springs and show GWAS results on TE methylation. They find that for most TE families winter lines are more methylated than springs. He focus a little on BARE1 copia-like elements, associated to drought and ABA responses, with higher CNV equatorial/sorth term T fluctuating regions. He shows a negative correlation between BARE1 CNV and yield. He shows nice boxplot-like plots showing individual data. He is asked to what extent the reference genome (Morex) affects his conclusion. He is also asked whether the seed source would affect his results, and to what extent his yield measurements are affected by the fact that he is planting barleys from other regions in North Europe.

Sorry, I missed the talks by Martin Groth (Helmholtz Zentrum München, Germany), Nick Loman (U. Birmingham, UK) and Tetsuya Higashiyama (Nagoya University, Japan).