REVIEW
Molecular genetics of puroindolines and related genes: regulation
of expression, membrane binding properties and applications
Mrinal Bhave Æ Craig F. Morris
Received: 5 November 2007 / Accepted: 7 November 2007 / Published online: 30 November 2007
Ó Springer Science+Business Media B.V. 2007
Abstract Kernel texture of wheat is a primary determi-
nant of its technological properties. Soft kernel texture
phenotype results when the Puroindoline a and Puroind-
oline b genes are present and encode the wild-type
puroindolines PINA and PINB, respectively, and various
mutations in either or both gene(s) result in hard pheno-
types. A wealth of information is now available that
furthers our understanding regarding the spatial and tem-
poral regulation of expression of Puroindoline genes.
Through the use of model membranes and synthetic pep-
tides we also have a clearer understanding of the
significance of the cysteine backbone, the tryptophan-rich
domain (TRD) and the helicoid tertiary structures of PIN
proteins in relation to their membrane-active properties.
Many studies suggest individual yet co-operative modes of
action of the PIN proteins in determining kernel texture,
and significant evidence is accumulating that the proteins
have in vivo and in vitro antimicrobial activities, shedding
light on the biological roles of this unique ensemble of
proteins. The puroindolines are now being explored for
grain kernel texture modifications as well as antimicrobial
activities.
Keywords Grain hardness Á Puroindolines Á
Grain softness protein Á Kernel texture Á
Wheat 9 Triticum Á Gene expression Á
Antimicrobial properties
Abbreviations
DAF Days after flowering (&days post-anthesis)
GSP Grain softness protein
NILs Near-isogenic lines
ns-LTPs Non-specific lipid-transfer proteins
QTL Quantitative trait locus/loci
SNP Single nucleotide polymorphism
TRD Tryptophan-rich domain
Introduction
The leading defining characteristic of common ‘bread’
wheat (Triticum aestivum L., AABBDD), in terms of world
trade and food technological applications, is its grain
hardness, or endosperm/kernel texture. The kernel texture
phenotype is associated with variations in a group of
*13 kDa proteins, comprised of two major proteins,
puroindoline a and b (PINA and PINB) (Morris 2002). The
two Puroindoline (Pin) genes Pina-D1 and Pinb-D1
(encoding PINA and PINB, respectively), and the gene
Grain softness protein-1 (Gsp-1) encoding the third minor
component of this protein group, GRAIN SOFTNESS
PROTEIN-1 (GSP-1), are all associated with the Hardness
(Ha) locus on chromosome 5D in common wheat. How-
ever, the homoeologous loci on chromosomes 5A and 5B
lack both Pin genes, these having been deleted during the
evolution of durum and thus common wheat. In contrast,
M. Bhave (&)
Environment and Biotechnology Centre, Faculty of Life and
Social Sciences, Swinburne University of Technology, P.O. Box
218, Melbourne, VIC 3122, Australia
e-mail: mbhave@swin.edu.au
C. F. Morris
U.S. Department of Agriculture, Agricultural Research Service,
Western Wheat Quality Laboratory, E-202 Food Science &
Human Nutrition Facility East, Washington State University,
P.O. Box 646394, Pullman, WA 99164-6394, USA
123
Plant Mol Biol (2008) 66:221–231
DOI 10.1007/s11103-007-9264-6
@Phil_Robichaud
@deepthiw
@JoseServera