What is meant by statement "the one who sees Dhamma sees dependent origination"? In MN 28 following was said :


  Now this has been said by the Blessed One: “One who sees dependent
  origination sees the Dhamma; one who sees the Dhamma sees dependent
  origination.”


My questions are :

What is meant by the above statement? &amp;
Is dependent origination not a Dhamma ?
This very question is exactly the topic of The Rice Seedling Sutra (Salistamba Sutra), one of the earliest known post-canonical sutras that can be classified as a missing link between Early Buddhism and Mahayana:


  [...] Venerable Śāriputra then said to the bodhisattva-mahāsattva Maitreya, “Maitreya, here today, the Bhagavān, gazing at a rice seedling, spoke this aphorism to the bhikṣus: ‘Bhikṣus, [just like this seedling was born from causes and conditions, the twelve nidanas occur in succession to one another. Verily,] whoever sees dependent arising sees the Dharma. Whoever sees the Dharma sees the Buddha.’ [...] Maitreya, what is the meaning of this aphorism spoken by the Sugata?  
  
  1) What is dependent arising? 2) What is the Dharma? 3) What is the Buddha? 4) How does one see the Dharma by seeing dependent arising? 5) How does one see the Buddha by seeing the Dharma?”
  
  The bodhisattva-mahāsattva Maitreya then replied to the venerable Śāradvatīputra, “Venerable Śāriputra, you want to know what dependent arising is in the statement made by the Bhagavān [...]   
  
  Well,   
  
  
  the phrase dependent arising means that something arises because something else already exists; something is born because something else was already born.  [...]
  what is the Dharma? The Dharma is the eightfold path of the noble ones [...] This eightfold path of the noble ones, combined with the attainment of its results and nirvāṇa, is what the Bhagavān has called the Dharma [...]
  who is the Bhagavān Buddha, [the Dharma-Born]? A buddha is so-called because of comprehending all dharmas; is endowed with the wisdom eye of the noble ones and the body of Dharma [...]
  how does one see dependent arising? On this point the Bhagavān said, ‘One who sees dependent arising as constant, without life force, devoid of life force, true, unmistaken, unborn, not arisen, uncreated, uncompounded, unobstructed, imperceptible, tranquil, fearless, incontrovertible, inexhaustible, and by nature never stilled, [...] clearly understands the Dharma of the nobles ones, and
  by thus acquiring such right knowledge, sees the Buddha -- the body of unsurpassable Dharma.’  
  
  
  [...]  
  
  [...] there are four links that serve as the cause for assembling this twelvefold dependent arising. What four links? Namely, 1) ignorance, 2) craving, 3) karma, and 4) consciousness. 
  
  
  Here, what is ignorance? That which perceives the six elements [earth, water, fire, wind, space, and consciousness] as a unit, a lump, permanent, constant, eternal, pleasurable, a self, a being, a life force, a creature, a soul, a man, an individual, a human, a person, me, and mine, along with the many other such variations of misapprehension, is called ignorance.  [...]
  The presence of such ignorance brings desire, aversion, and delusion toward objects. [...] three types of [karmic] tendencies accumulate: those that lead to meritorious states, those that lead to unmeritorious states, and those that lead to neutral states. 
  Karma [resulting from karmic tendencies] and afflictions [i.e. ignorance, craving, and pursuit of objects] cause the seed of consciousness to grow [...] [Consciousness dwells in the impressions produced by karma which are then deposited in the consciousness as representation of objects]
  That which distinguishes between individual objects is consciousness.  [...] When the seed of consciousness grows, planted in the field of karma, moistened by the water of craving, and strewn with the manure of ignorance, the sprout of name and form manifests.
  
  
  [...] there is nobody at all who transmigrates from here after death and is born elsewhere, and yet, because there is no deficiency of requisite causes and conditions, the result of karma nonetheless manifests [...] although things are devoid of owner, devoid of ownership, ungraspable, space-like, and their nature is the mark of illusion, because there is no deficiency of requisite causes and conditions, the seed of consciousness born of karma and afflictions will nonetheless produce the sprout of name and form [...] 
  
  [...]
  “Thus, this twelvefold dependent arising — which comes from several different causes and from several different conditions, is neither permanent nor impermanent, is neither compounded nor uncompounded, is not without any cause or condition, is not an experiencer, and is not something exhaustible, something destructible, or something that ceases — has proceeded from time immemorial, without interruption, rolling along like a flowing stream.  
  
  [...]
  
  Venerable Śāriputra, whoever sees with perfect wisdom this dependent arising, perfectly taught by the Bhagavān, as it actually is — as always and forever without life force, devoid of life force, true, unmistaken, unborn, not arisen, uncreated, uncompounded, unobstructed, imperceptible, tranquil, fearless, incontrovertible, inexhaustible, and by nature never stilled — whoever fully and truly sees it as unreal, vain, hollow, unsubstantial, as a sickness, a boil, a thorn, as miserable, impermanent, painful, empty, and no-self, [thereby restricting the power of ignorance-produced karmic tendencies] -- such a person does not reflect on the past thinking, ‘Did I exist in the past, or not? What was I in the past? How was I in the past?’ Nor does such a person reflect on the future thinking, ‘Will I exist in the future, or not? What will I be in the future? How will I be in the future?’ Nor does such a person reflect on the present thinking, ‘What is this? How is this? Being what, what will we become? Where does this being come from? Where will it go when transmigrating from here at death?’
  Whichever dogmas mendicants-and-brahmins hold throughout the world, whether they involve belief in a self, belief in a being, belief in a life force, belief in a person, or belief in rites and rituals -- such dogmas, prone to agitation and dullness, are all abandoned at that time. Fully understood as false, these dogmas are severed at the root and wither like the head of a palm tree, never to arise or cease in the future.
  
  [...]


The meaning of this, as I understand it: just as someone looking at a moist seed in the ground sees the potential sprout - same way someone looking at the seeds of ignorant consciousness in the ground of karma sees the inevitable arising of individual experience, and someone who understands this dependent origination of individual experience - necessarily understands ignorance, craving, and origination of suffering. Since s/he understands how it originates -- s/he understands how it can stop. S/he understands the ground, the goal and the path. This understanding is called "seeing the Dharma".

Seeing the Dharma, there is no more ignorance, no craving or aversion, no attachment, no selfish goal-making, no I-projecting, no conflict between "is" and "should", no suffering, no birth and no death. Whatever remains is suchness. 

Seeing the Dharma is seeing Buddha, because Buddha is born from the seeds of Dharma and Dharma is spread by Buddha, just like with rice plant and rice.