Scent, flowers, all that JAZ

28 Apr 2017 - By: Jonathan Ingram

Scent, flowers, all that JAZ

Jasminum sambac
Jasminum sambac. Photo: Prof. Huajie Liu

By Jonathan Ingram, Journal of Experimental Botany

It isn’t so long ago that ‘jasmine’ simply meant exquisite scent, understated flowers or a fragrant and refreshing tea. The discovery that the methyl ester of (–)-jasmonic acid (JA) not only provides the fragrance but acts as a phytohormone changed all that, but the past decade has seen an opening up of the field following the critically important identification of JAZ proteins in 2007. The latest special issue from Journal of Experimental Botany celebrates 10 years of research on JAZ proteins, with an editorial from Ziqiang Zhu and Richard Napier providing a concise perspective on this burgeoning area of research and drawing together the themes in this series of timely and in-depth reviews. 

Editorial: Jasmonate – a blooming decade

Special Issue: The Flowering of Jasmonate Research

Jasmonates – jasmonic acid and its derivatives – are involved in the regulation of vital processes encompassing the full arc of a plant’s life, from germination through to flowering and senescence. They are also important in defence, stress tolerance and many other areas. With such wide involvement across plant development, it is no surprise to find a long evolutionary history, which Zhu and Napier explain. To become active, jasmonic acid is converted to its amino acid conjugate (+)-7-iso-jasmonoyl-L-isoleucine (JA–Ile), and all land plant lineages have the full set of enzymes for biosynthesis and catabolism of the conjugate. 

The papers in the issue cover all the critical developments in our understanding of jasmonates, such as the discovery of Coronatine Insensitive 1 (COI1) in the 1990s (cloned in 1998) and the story which unfolded from there. Zhu and Napier:

‘COI1 encodes a leucine-rich repeat type F-box protein that assembles in an SCF protein complex; this targets substrate proteins for degradation, a process which initiates signalling … Suppressor screens and protein complex purification approaches failed to find the COI1 substrate(s), although it was only a few years later that the crystal structure of COI1 in complex with its ligand JA-Ile and its co-receptor (a jasmonate ZIM-domain, JAZ, protein) was solved.’

They look at the ‘landmark breakthrough’ which was the identification of JAZ proteins in 2007, with independent findings from three different research groups led by John Browse, Roberto Solano and Edward Farmer (JAZ1, JAX3 and JAZ10, respectively). And, for example, they go on to discuss interactions between JAZ proteins and MYC transcription factors. It is a still-developing narrative, both in terms of our understanding of the fundamental control of plant development and commercial spin-offs: 

The basic helix-loop-helix (bHLH) type transcription factor MYC2 was identified as necessary in JA signalling just over a decade ago … Much recent research on the bHLH family has drawn attention to the family members that elicit specialized metabolic pathways in response to JAs …There is immense interest in exploitation of such switchable pathways where they mediate the biosynthesis of high-value chemicals. A number of important pharmaceutical products are plant protectants, induced in response to trauma via JA signalling, making both JA and JA signalling attractive synthetic biology targets. 

Each review covers a different aspect in detail, including evolution, biosynthesis and metabolism, and role of bHLH transcription factors, as well as action in growth and development, senescence and stress, and defence against pathogens

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Journal of Experimental Botany publishes an exciting mix of research, review and comment on fundamental questions of broad interest in plant science. Regular special issues highlight key areas.



Author: Jonathan Ingram
Category: Plant Biology
Jonathan Ingram - Author Profile

Jonathan Ingram

Jonathan Ingram is Senior Commissioning Editor/ Science Writer for Journal of Experimental Botany. Jonathan moved from lab research into publishing and communications with the launch of Trends in Plant Science in 1995, then going on to New Phytologist and, in the third sector, Age UK and Mind.