Are We on the Right Track: Can Our Understanding of Abscission in Model Systems Promote or Derail Making Improvements in Less Studied Crops?

Abstract

As the world population grows and resources and climate conditions change, crop improvement continues to be one of the most important challenges for agriculturalists. The yield and quality of many crops is affected by abscission or shattering, and environmental stresses often hasten or alter the abscission process. Understanding this process can not only lead to genetic improvement, but also changes in cultural practices and management that will contribute to higher yields, improved quality and greater sustainability. As plant scientists, we have learned significant amounts about this process through the study of model plants such as Arabidopsis, tomato, rice, and maize. While these model systems have provided significant valuable information, we are sometimes challenged to use this knowledge effectively as variables including the economic value of the crop, the uniformity of the crop, ploidy levels, flowering and crossing mechanisms, ethylene responses, cultural requirements, responses to changes in environment, and cellular and tissue specific morphological differences can significantly influence outcomes. The value of genomic resources for lesser-studied crops such as cranberries and grapes and the orphan crop fonio will also be considered.

The PIP Peptide of INFLORESCENCE DEFICIENT IN ABSCISSION Enhances Populus Leaf and Elaeis guineensis Fruit Abscission

“…Molecular genetic research on floral organ abscission with the model species Arabidopsis thaliana has led to tremendous progress in deciphering the underlying mechanisms and to the definition of details concerning the stages of organ abscission [4,5,6,7,8]. While these signalling and molecular pathways identified in Arabidopsis provide insight into the stages and signalling mechanisms of organ abscission, it is not known whether this information can be translated to all species and all organ types that are shed [9]. Based on the current model derived from these studies, the four stages of abscission include: (1) the ontogeny of the AZ, (2) the acquisition of AZ cell competence to integrate and respond to abscission signals, (3) the activation of AZ cells by abscission signals that induce the de novo synthesis of cell wall-modifying enzymes that cause cell wall loosening and rounding of the AZ cells, and (4) the trans-differentiation of remaining AZ cells to produce a protective layer [8,10].…”

Identification and expression of genes associated with the abscission layer controlling seed shattering inLolium perenne

“…This suggests that perennial ryegrass has a high degree of synteny with these species in terms of genetic control of the seed shattering trait, and that at least some of the candidate genes may potentially share functional similarity to those in rice and other monocot crops. A similar strategy was used by Patterson et al (2016) attempting to identify mutations in qSH1 in Digitaria exilis (fonio), an orphan grain crop in Africa, in which seed shattering is also a serious concern.…”

Allele-Specific Interactions between CAST AWAY and NEVERSHED Control Abscission in Arabidopsis Flowers

“…With the growing accessibility of approaches to identify the transcriptomes of abscission zone cells in model as well as crop plants using laser capture microdissection ( Cai and Lashbrook, 2006 , 2008 ; Agustí et al, 2009 ) and RNA sequencing ( Niederhuth et al, 2013 ; Kim et al, 2016 ; Sundaresan et al, 2016 ), the agronomic value of using model plants to study abscission is under debate ( Patterson et al, 2015 ). The recent discovery that drought-triggered leaf abscission is dependent on the activities of IDA, HAE/HSL2, and NEV ( Patharkar and Walker, 2016 ) significantly enhances the usefulness of Arabidopsis as a model system.…”