Do pea nodulated roots have a memory like a sieve or like an elephant when faced with recurrent water deficits ?
Résumé
In the current context of climate change, periods of water deficit occur more frequently
along the crop cycle, leading to high yield losses. To limit the negative impact of recurrent
water deficits, plants can adapt, via the mobilization of “stress memory”, allowing them to
respond to a subsequent stress in a faster and/or more intensive manner. After a first stress
event, plants can keep an imprint of this stress via the induction of epigenetic (e.g. memory
gene regulation), physiological (e.g. stomatal closure) and molecular (e.g. compound
accumulation) changes. When maintained between two stress periods, these changes may
prepare plants for a subsequent water deficit.
This work addresses the potential role of stress memory in plant adaptation to recurrent water
deficits with a special focus on plant hydro-mineral uptake by roots. For this purpose, an
experiment was conducted on the high throughput phenotyping platform (4PMI, Dijon, France),
where several frequencies of water deficits were applied to pea plants. An integrative
approach, including a structure-function ecophysiological framework characterizing plant
hydromineral nutrition (nutrients and beneficial elements), enriched with root and nodule
transcriptomic analyses (RNA-seq), revealed the mechanisms underlying the “memory effect”
throughout the plant cycle. We will discuss the role of memory genes during recurrent stresses
and plant strategies to acquire water as well as macro- and micro-nutrients more efficiently
during recurrent stresses. This work offers the new perspective of considering plant memory
in the design of ideotypes better adapted to multiple stress events in a context of climate
change.
Study conducted in the framework of the EAUPTIC project, supported by the “Fond Unique
Interministériel" (n° 3870401/1), BPIFrance (n° DOS0097244/00), the Regional Council of
Burgundy (n° DOS0133465/00), Dijon Metropole (n° CONV-DM2018-118-20180820), and the
Fonds Européen de Développement Régional (n° 2018-6200FEO003S01889).