Flower up RNA (SAUR), and auxin response factor

development and sex determination is highly regulated by crosslink of
endogenous hormones. Auxin plays a pivotal role in regulation of plant growth such as embryogenesis, organogenesis,
tropic growth, root architecture, flower and fruit development, tissue and
organ patterning, and vascular development.
Primary/early auxin response genes
of gene families, auxin/indole-3-acetic acid (Aux/IAA), Gretchen
Hagen3 (GH3), small auxin up RNA (SAUR), and auxin response
factor (ARF) have been well
known. In Jatropha,
AUX/IAA, SAUR were associated with sex differentiation.  Transcriptome analysis of Jatropha
identifies genes associated with auxin biosynthesis and signaling such as AUX1, TIR1, AA14 and ARFs. ARFs either activates or represses the expression of auxin
response genes. In Jatropha,ARF1 acts as a
transcriptional repressor and ARF5
as a transcriptional activator. Trp-dependent auxin biosynthesis is the main source of auxin production
for formation reproductive organ and patterning of embryos (wang et al 2015).
In this pathway, TAA1/TAR1/TAR2 enzymes produces indole-3-pyruvic acid,
which is then converted into IAA by YUCCA (YUC) flavin-dependent monooxygenases
(Novak et al., 2012; Korasick et al., 2013; Ljung, 2013; Zhao, 2014).
These YUCs produces auxin during
stamen primordia formation by YUC1 and YUC4 and late stamen development by YUC2
and YUC6 (Cheng et al., 2006; Cecchetti et al., 2008). In
mature gynoecia, YUC4 and YUC8 were expressed in the style and YUC2 in carpel
valve tissues (Cheng et al., 2006; Martínez-Fernández et al., 2014). SPARSE INFLORESCENCE1 (YUC-like) mutants resulted in small ears and few
kernels in maize (Gallavotti et al., 2008a). ). TAA1 was associated with
early gynoecial development and
was localized within the medial domain of the gynoecia (Stepanova et al., 2008). Increased expression of ARF10,
16, 17 and 18 caused floral organ loss and abnormal
female fertility in Arabidopsis and less seed set rice (Liu
et al., 2010, (Huang et al., 2016a). PIN-FORMED (PIN1), an auxin efflux carrier protein has
been studied in Arabidopsis for its role in ovule formation. PIN1
directs the auxin flow from base of the gynoecium to the top of the gynoecial
tube (Larsson et al., 2014; Moubayidin and Østergaard, 2014). BARREN INFLORESCENCE1 (BIF1) and  BARREN
genes identified in maize regulates polar auxin transport via up-regulating PIN1a (Gallavotti et al., 2008b). bif1 and bif2 mutants have
reduced number of spikelets/florets and floral organs, and consequently fewer
kernels in maize (McSteen and Hake, 2001; Barazesh and McSteen, 2008; Skirpan et al., 2009). Ectopic
expression of TAPETUM DETERMINANT1 (TPD1)  causes abnormal ovule and seed development via
altering auxin signaling (Huang et al., 2016b,c. The rice gene LAZY1 (LA1), which encodes a novel
grass specific protein, is a negative regulator of polar auxin transport (Li et al., 2007). Spikelets
in la1-ref (La1 orthologue) either are not fully developed or
undergo abortion in the tassel tip.