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).
