- HUANGLONGBING: DEVASTATING DISEASE OF CITRUS 321
The story of HLB is tied closely with Dr. Jose Bov ́e. For most of the
past 50 years, Professor Bove and his colleagues and collaborators have ́
led the world in HLB research. Dr. Bove’s contributions to our under- ́
standing of the pathology, etiology, molecular biology, and control of
HLB are without equal and constitute the foundation for contemporary
HLB research. There are few published reports addressing HLB that do
not include at least one, and frequently multiple, citations of Dr. Bove’s ́
findings. Throughout his illustrious career, Dr. Bove has collaborated ́
with citrus pathologists, entomologists, and agronomists around the
world as HLB has spread through important citrus-producing regions.
In 2006, shortly after HLB was discovered in the Western Hemisphere,
Dr. Bove published an extensive review of the history, etiology, biology, ́
epidemiology, detection, geographical distribution, and management
of HLB (Bove 2006). A review by da Grac ́ ̧a (1991) is also a valuable
resource for those seeking additional historical details regarding HLB
prior to its discovery in the Western Hemisphere. More recently, Wang
and Trivedi (2013) reviewed HLB with a microbiological focus. The
most recently published review (da Grac ̧a et al. 2015) focused on citrus
immune responses along with genetics and transmission of the bacte-
rial causal agent of HLB. Our goal in this review is to look at HLB from
a plant physiology perspective, with particular attention to the role of
starch starvation and development of the HLB syndrome along with
changes in fruit quality that are some of the many symptoms of HLB.
The first descriptions of HLB date back to the late 19th-century China
when a citrus disorder characterized by irregular chlorosis on leaves
and shoots was described and attributed to nutritional deficiencies.
Much of the seminal work on HLB was conducted in Asia and was
not generally available to Western researchers. There are two recog-
nized forms of HLB, the Asian form and the African form. The Asian
form of HLB is the most widespread and is having the greatest impact
on worldwide citrus production (da Grac ̧a 1991; Bove 2006; Gottwald ́
2007; Gottwald 2010). Prior to 2004, HLB had not been found in the
Western Hemisphere, making the disease of little concern and not a
research priority in that region.
Everything changed in 2004 when HLB was confirmed in Brazil
(Coletta-Filho et al. 2004) and shortly thereafter in Florida (Halbert
2005). da Grac ̧a (1991) reviewed 278 papers on HLB related topics, with
most from obscure journals and conference proceedings. Since 2005
until the time of this writing, at least 550 additional papers focused on
various aspects of HLB including microbiological, entomological epi-
demiological, host physiology, transcriptomics, genomics, proteomics,
and fruit/juice quality have been published. By 2013, the real and